Zongquan Deng

• Professor
• Engineer at Harbin Institute of Technology

Reinforcement learning (RL) has demonstrated impressive performance in legged locomotion over various challenging environments. However, due to the sim-to-real gap and lack of explainability, unconstrained RL policies deployed in the real world still suffer from inevitable safety issues, such as joint collisions, excessive torque, or foot slippage...

The sensing capabilities of a soft arm are of paramount importance to its overall performance as they allow precise control of the soft arm and enhance its interaction with the surrounding environment. However, the actuation and sensing of a soft arm are not typically integrated into a monolithic structure, which would impede the arm’s movement and...

With end-effector force estimation, manipulators can safely interact with the environment or operators, eliminating the need for conventional wrist sensors that measure force and torque. This paper introduces a new approach to estimating the force exerted by the end-effector, utilizing a two-step method. The first step is to build an accurate semip...

Reinforcement learning (RL) has demonstrated impressive performance in legged locomotion over various challenging environments. However, due to the sim-to-real gap and lack of explainability, unconstrained RL policies deployed in the real world still suffer from inevitable safety issues, such as joint collisions, excessive torque, or foot slippage...

In surface exploration missions, wheeled planetary vehicles have difficulty traveling on asteroids due to their weak gravitational fields. With the rapid development of hardware performance and control methods, quadruped robots have great potential to serve in asteroid exploration. When deploying or controlling the jumping motions of a quadruped ro...

Specialized robots, such as legged robots and unmanned aerial vehicles (UAVs), are commonly regarded as effective platforms for aiding in search and rescue (SAR) missions. However, existing approaches often decouple the tasks between UAVs and legged robots, for instance, using UAVs for mapping and legged robots for operation. Such feature hinders t...

Variable wheelbase wheeled mobile robot (VW‐WMR) is capable of maneuvering flexibly and traversing on rough and soil terrains within confined spaces. While the steering radius of the robot model can be robustly changed by the variable wheelbase length, a challenge is posed in accurately tracking a predefined trajectory through the alteration of whe...

This article aims to address the in-orbit assembly needs of truss structures in space missions by designing a robot capable of moving on trusses and manipulating parts. To enhance the stability of the robot during movement and part manipulation, inspiration was drawn from the Dynastes Hercules beetle. Building upon detailed research on the Dynastes...

Crewed lunar vehicles (CLVs) significantly enhance astronauts’ exploration range and efficiency on the moon, paving the way for more comprehensive scientific research. Utilizing computer simulations offers an effective alternative to conducting experiments in low‐gravity conditions if backed up by appropriate model validation. This study introduces...

This paper addresses the problems of valve-turning operation in rescue environments where a wheeled mobile manipulator (WMM) is employed, including the possible occurrence of large internal forces. Rather than attempting to obtain the exact position of the valve, this paper presents a solution to two main problems in robotic valve-turning operation...

This paper presents a pyrotechnic-driven large flexible expansion mechanism for aerospace applications, where a flexible link is added to the mechanism to enhance its high speed performance. To evaluate the impact of adding a flexible link on the high-speed motion of a mechanism, and to study the coupling relationship between the pyrotechnic drive...

The planned missions to explore the surfaces of the Moon and Mars require high exploration efficiency, thus imposing new demands on the mobility system of planetary rovers. In this paper, a design method for a high-speed planetary rover (HPR) is proposed, and the representative configurations are modeled and simulated. First, the influence of the p...

Origami-inspired metamorphous structures can adjust their shapes and mechanical behaviors according to operational requirements. However, they are typically composed of nonrigid origami, where required facet deformation complicates actuation and makes them highly material dependent. In this study, we present a type of origami metamorphous structure...

A novel event‐triggered heuristic dynamic programming (HDP) algorithm is proposed for the near‐optimal control of uncertain discrete‐time nonlinear input‐affine systems. Based on input‐to‐state stability (ISS) analysis, a new event‐triggered mechanism (ETM) is designed. Under constant coefficients, a Lipschitz‐like assumption that forms the basis o...

Heavy‐duty hexapod robots have impressive stability, high load‐bearing capacity, and exceptional adaptability to rugged terrains. They are capable of working in challenging outdoor environments such as planetary exploration, disaster relief and mountain transportation. Their ability to traverse terrain requires effective motion planning and accurat...

The truss static structure system has excellent large load and lightweight characteristics. It is easy to embed actuators by substituting specific members in the structure and has the potential for multi-dimensional space deformation. Inspired by uniform tessellation structures, this paper proposes a novel shape morphing mechanism (SMM) based on th...

Unmanned helicopters equipped with adaptive landing gear will dramatically extend their application especially in dealing with challenging terrains. This study presents a novel cable-driven legged landing gear (CLG) with differential transmission for unmanned helicopters in complex landing environments. To obtain the preferred configuration of the...

Telescopic wing requires changing the wingspan under aerodynamic load. Structural deformation caused by forces and moments will result in increased driving forces or even stagnation. Deformation and distributed contact force of linear motion pair of the load-bearing mechanism which considers the geometric nonlinearity of guide rail is necessary to...

Yutu-2 rover conducted an exciting expedition on the 41st lunar day to investigate a fin-shaped rock at Longji site (45.44°S, 177.56°E) by extending its locomotion margin on perilous peaks. The varied locomotion encountered, especially multi-form wheel slippage, during the journey to the target rock, established unique conditions for a fin-grained...

Multiple ultrasonic percussive drill cross-drilling anchoring helps to achieve long-term, secure attachment of sampling platforms in extreme environments. Ultrasonic percussive drills require less weight-on-bit (WOB) and lower power than conventional drills, making them more suitable for asteroid anchoring mission. Choosing a suitable WOB control m...

Wheeled mobile robots (WMRs) with variable wheelbases are capable of traveling on deformable terrains and handling complex detection tasks. While the variable wheelbase length of WMR allows it to interact with the terrains adaptively, enhancing its mobility, it brings a control challenge. Inspired by the worm's movement of stretching body at differ...

Deep reinforcement learning (DRL) methods have shown significant promise in controlling the movement of quadruped robots. However, for systems like hexapod robots, which feature a higher-dimensional action space, it remains challenging for an agent to devise an effective control strategy directly. Currently, no hexapod robots have demonstrated high...

Continuum robots recently have gained remarkable potential in exploring unstructured environments due to the merits of adaptability and flexibility. However, achieving flexible and steerable deformation in wide-range three-dimensional (3-D) spaces is still challenging for continuum robots. This article presents the design and control of a novel inf...

Identifying terrain parameters is important for high-fidelity simulation and high-performance control of planetary rovers. The wheel–terrain interaction classes (WTICs) are usually different for rovers traversing various types of terrain. Every terramechanics model corresponds to its wheel–terrain interaction class (WTIC). Therefore, for terrain pa...

The sparse atmosphere on the surface of Mars provides the necessary flight conditions for Mars unmanned aerial vehicles (UAVs) to perform low-altitude flights. This work presents a comprehensive overview of key technologies in the development of Mars UAVs, with a specific focus on rotary-wing Mars UAVs. It summarizes prototypes of rotary-wing Mars...

Morphing leading edge has great potential to enhance the flight efficiency of a vehicle due to its smooth and seamless surface. To improve the computational efficiency of leading-edge bending deformation, this paper developed a parametric method for modeling the large planar deflection of the flexible skins. Based on the chain beam constrained mode...

The growing interest in entry vehicles for Mars exploration has underscored the need for a decelerator with the ability to deploy and withstand significant loads. To address this challenge, we proposed a design concept for an entry vehicle featuring semi-rigid trapezoid deployable structures (SRTDS). This design involves a deployable mechanism cons...

The cable-strut structure optimisation of a large space cable-strut tensioned parabolic cylindrical antenna is studied. Firstly, the deployment mechanism is designed, and the degree of freedom and kinematics analysis of the mechanism are conducted. Secondly, a complete tension cable configuration with 58 tension cables in 24 categories is establish...

The Moon and Mars have numerous lava tubes, which provide shelter from the extreme temperatures and high-energy particle radiation on the planets’ surfaces. This makes them ideal candidates for future scientific exploration and construction of human bases. Robots for uncharted environments must be developed to provide advance information before ast...

Soft robots have tremendous potential for applications in various fields, owing to their safety and flexibility embedded at the material level. Soft robots, especially bio-inspired soft legged robots, have become one of the most active fields of current research in robotics thanks to their superior mobility and ability to face complex terrains. How...

In this study, a finite‐time online optimal controller was designed for a nonlinear wheeled mobile robotic system (WMRS) with inequality constraints, based on reinforcement learning (RL) neural networks. In addition, an extended cost function, obtained by introducing a penalty function to the original long‐time cost function, was proposed to deal w...

Recently, the deployable antenna structure is designed and built extra larger to address the lack of observation accuracy and high resolution. However, this will bring new challenges for the performance testing of the prototype in a terrestrial environment. Similitude theory is a branch of methodology method that can reflect the basic configuration...

The aerodynamic properties of rotor systems operating within low Reynolds number flow field conditions are profoundly influenced by their geometric and flight parameters. Precise estimation of optimal airfoil parameters at different angles of attack is indispensable for enhancing these aerodynamic properties. This study presents a technique for opt...

Based on actor-critic neural networks (NNs), an optimal controller is proposed for solving the constrained control problem of an affine nonlinear discrete-time system with disturbances. The actor NNs provide the control signals and the critic NNs work as the performance indicators of the controller. By converting the original state constraints into...

Autonomous navigation plays an increasingly crucial role in rover-based planetary missions. End-to-end navigation approaches developed upon deep reinforcement learning have enabled great adaptability in complex environments. However, most existing works focus on geometric obstacle avoidance thus have limited capability to cope with ubiquitous non-g...

In response to the requirements of large-scale space in-orbit assembly and the special environment of low gravity in space, this paper proposes a small robot structure with the integration of assembly, connection, and vibration reduction functionalities. Each robot consists of a body and three composite mechanical arms-legs, which can dock and tran...

The legged robot has better adaptability to terrain in the process of moving and has been considered for future planetary exploration missions. As the part of direct contact with planet soil, the foot will directly affect movement performance and control effect of the legged robot. In this paper, the advantages and disadvantages of various foot con...

In the spin-off acceleration stage during high-speed rotation in space, the deployable arm of the space gravity simulation device must withstand a large axial centrifugal force and a driving torque. In this paper, a large-scale high-speed rotating deployable arm is proposed, and the relevant characteristics during the rotation process are analyzed....

Background In the manufacturing setup process of weapons, aviation, and aerospace, docking assembly is a key component in determining manufacturing efficiency and quality. The traditional docking method uses manual alignment, which depends on the experience and operation level of the workers, so the docking accuracy is low and the installation spee...

Planetary rovers with lugged-wheels are the primary equipment for Mars exploration, and as exploration missions become more complex, rovers are expected move into more challenging terrains. When moving over soft sand or slopes, lugged-wheels experience high slip and heavy sinkage, and an explicit sinkage prediction model for lugged-wheels is not av...

The increasing interest in decelerators utilized in Mars exploration has heightened the need for a decelerator with the function of deploying and a low ballistic coefficient. This paper designed a novel deployable mechanism based on 7R-6R double-loop units for Mars decelerators. First, this paper designed a new double-loop deployable unit coupled b...

Physical characteristics of terrains, such as softness and friction, provide essential information for legged robots to avoid non-geometric obstacles, like mires and slippery stones, in the wild. The perception of such characteristics often relies on tactile perception and vision prediction. Although tactile perception is more accurate, it is limit...

In this paper, in order to obtain the influence of translational clearance joint on the dynamic characteristics transient of deployment mechanism underload large unbalance, the contact state and relative motion of slider and guide rail are firstly analyzed to illustrate the dynamics of slider and guide rail during the transient motion of the multi-...

The electrically driven large-load-ratio six-legged robot with engineering capability can be widely used in outdoor and planetary exploration. However, due to the particularity of its parallel structure, the effective utilization rate of energy is not high, which has become an important obstacle to its practical application. To research the power c...

Reconfigurable mechanisms attract increasing attention for the characteristic to change structure configurations and motion behaviors in various multifunctional systems. By drawing inspiration from a kirigami fold, this paper presents a metamorphic double-loop linkage with multiple single-DOF reconfiguration branches, which is generated through com...

This paper investigates initial-pose estimation (Cartesian position and orientation) for redundant cable-driven parallel robots (CDPRs). As the forward kinematics cannot be performed if the robot is equipped with incremental sensors, a calibration method using force sensors is proposed. The self-calibration problem is formulated as a non-linear le...

In deep space exploration, ultrasonic drill is an effective tool for asteroid landing anchoring. As the drive time grows, the resonance frequency of the ultrasonic drill piezoelectric transducer is offset, which leads to a serious degradation of the matched ultrasonic drill speed. In order to solve the problem that the performance of the matched tr...

Interaction with the terrain is essential for legged robots to adapt to complex environment. Field terrain could be steep, slippery, and muddy. Legged robots may sink on sand or mud and slip on ice or snow. To address such problems, foot–terrain interaction models have been developed to preestimate the sink or slip state of the robot and models are...

Soft robots have become important members of the robot community with many potential applications owing to their unique flexibility and security embedded at the material level. An increasing number of researchers are interested in their designing, manufacturing, modeling, and control. However, the dynamic simulation of soft robots is difficult owin...

Technology advancement in modern planetary exploration has extended extraterrestrial geological science by sending rovers on challenging, possibly risky but highly scientific-valuable ventures, such as ascending towards the crater walls, traversing steep slopes of sand dunes and travelling through the lava tube. On the 41st lunar day, the first lun...

Cable-driven parallel robots (CDPRs) with redundant drives represent a class of mechanisms where the force distribution in cables is a core problem. The hybrid joint-space control strategy, where the chosen redundant cables are force-controlled, whereas the remaining ones are length-controlled in the joint space. Because different cable combination...

The Mars rotorcraft can help the Mars rover to optimize the driving route and explore more efficiently. However, the thin and cold Martian atmosphere can heavily increase the consumed power of the rotorcraft blades and reduce the generated thrust, leading to the reduction in power loading. The aerodynamic force generated by the Mars rotorcraft blad...

In this investigation, the integrated attitude and landing control scheme for quadruped robots in asteroid landing mission scenario is discussed. Compared with the gravitational field environment of the Earth, the gravitational field near most asteroids has a smaller gravitational acceleration, a non-negligible horizontal acceleration component, an...

In June 2021, at the GLEX-2021 conference in St. Petersburg, the leaders of the Chinese and Russian space agencies presented the ILRS roadmap, which formulated the goals, stages of creation and key areas of relevant design research: • Technologies of long-term energy supply; • Technologies for mounting and assembling large sections of ILRS; • Luna...

Space missions have become diversified in recent years, where connection and separation devices play a crucial role as key components of various spacecraft. Traditional pyrotechnic devices have the advantages of large carrying capacity, rapid motion and functional reliability. However, their shortcomings such as great release shock, poor safety, un...

Planetary rovers may traverse terrains with complex geometries and variable physical properties, but their mobility behaviors are complicated and difficult to simulate precisely. This article focuses on high-fidelity dynamic modeling and simulation for a type of rovers that incorporate single-input-multi-output joints to enhance terrain adaptabilit...

The landing of a probe on the surface of an asteroid can produce a stable operating platform and obtain vital data describing the mechanical response of the asteroid material. The fine-grained regolith area on the asteroid surface is essential in cushioning the probe from impact energy and in avoiding the risk raised by the large protruding rocks d...

The probes landing on the surfaces of the asteroids can increase the scientific return of the exploration missions and also promote the development of deep space resources. Because of its excellent applicability to the uneven terrain and a lighter configuration than the four-legged mechanisms, the three-legged cushioning mechanisms are suitable for...

Asteroid exploration has become a research hotspot, and anchoring probes to asteroids is essential for in situ scientific detections. The influence of ultrasonic drilling force-closure anchoring parameters on the anchoring performance and its influence mechanism are studied based on discrete element simulation. An anchoring simulation model is esta...

Focused on an asteroid probe with three-legged cushioning, this paper discusses the effects of the asymmetric configuration and the element forces form of the planarized cushioning mechanism on the method for developing the landing experiment. The main objectives are to present an accurate experimental analysis of the planar landing and to facilita...

It is important for Mars exploration rovers to achieve autonomous and safe mobility over rough terrain. Terrain classification can help rovers to select a safe terrain to traverse and avoid sinking and/or damaging the vehicle. Mars terrains are often classified using visual methods. However, the accuracy of terrain classification has been less than...

Deployable membranes are being increasingly applied in numerous space projects owing to their light weight, small stowage volume and capacity for use at large scales. The geometric design of biomimetic folding is studied to design crease patterns for triangular deployable membranes applied in space. Various crease designs for triangular membranes b...

Asteroid exploration is significant for studying the origin of the solar system, establishing planetary defenses, and alleviating the resource crisis of the Earth. Asteroid anchoring is the basis of in-situ exploration and resource development and utilization. Therefore, the performance of asteroid force-closure anchoring is investigated using the...

Percussive ultrasonic drills participate in asteroid exploration missions. Since space environments are complex and working loads vary dramatically, it is necessary to design a drive that better matches the percussive ultrasonic drill to make it achieve high-speed drilling with low power consumption. Impedance characteristics under different load c...

For redundant cable-suspended parallel robots, gravity imposes a predictable minimum or maximum limit on the tension in all cables. The hybrid joint-space control strategy is adopted in this study. In this case, the chosen redundant cables are force-controlled, whereas the remaining ones are length-controlled in the joint space. This strategy aims...