Figure - available from: Intelligent Service Robotics
This content is subject to copyright. Terms and conditions apply.
![The structure of the variable stiffness joint [18]. a Parts of the variable stiffness joint, b Spring deformation during joint rotation, c Pivot joint and lever](publication/358802385/figure/fig2/AS:1159809105707008@1653531447132/The-structure-of-the-variable-stiffness-joint-18-a-Parts-of-the-variable-stiffness.png)
The structure of the variable stiffness joint [18]. a Parts of the variable stiffness joint, b Spring deformation during joint rotation, c Pivot joint and lever
Source publication
![The MOD-AwAS variable stiffness joint [6]. a Stiffness change with the...](publication/358802385/figure/fig1/AS:1159809101504512@1653531446041/The-MOD-AwAS-variable-stiffness-joint-6-a-Stiffness-change-with-the-lever-mechanism-b_Q320.jpg)
![The structure of the variable stiffness joint [18]. a Parts of the...](publication/358802385/figure/fig2/AS:1159809105707008@1653531447132/The-structure-of-the-variable-stiffness-joint-18-a-Parts-of-the-variable-stiffness_Q320.jpg)
A variable stiffness actuator (VSA) is considered a promising mechanism-based approach for realizing compliant robotic manipulators. By changing the stiffness of each joint, the robot can modulate the stiffness of the entire system to enhance safety and efficiency during physical interaction with other systems. This paper presents a feedforward met...
Similar publications
This paper presents a synchronous proportional derivative (PD) control method using a time delay estimator (SPD-TDE) for a four-degree-of-freedom (DOF) parallel robot in practice. The proposed control is a method that is developed from a synchronous PD control method combined with a time delay estimator to guarantee the tracking objectives and sync...
Citations
... Open-loop approaches include variable geometry [39,40], redundant actuation [41,42], and implementation of variable stiffness actuators [43,44]. A combined use of real-time kinematic redundancy and variable stiffness actuators for achieving stiffness modulation was proposed in Ref. [38]. ...
This paper presents a control strategy for the stiffness regulation of parallel manipulators based on the implementation of a simple proportional controller. Starting from the assignment of the stiffness or compliance matrix in the task space, defined by the application-specific requirements, a proper control action is calculated by considering the translational and rotational compliances of the end-effector. The proposed approach is applied in SE(2) and SE(3), addressing the analysis of the 3RRR planar parallel manipulator and the 6UPS Stewart-Gough platform. The proposed control scheme decouples the effects of the applied force and moment on the end-effector displacement and rotation. Numerical examples are presented, with multibody simulations performed to verify the effectiveness of the proposed approach. Effect of friction in the active and passive joints is also investigated.
... = AF B (13) where denotes the force exerted on the scissors. The components of , and can be referenced in the appendix. ...
... Therefore, we have nine equations and ten variables (refer to Appendix), meaning we still need additional condition to obtain a unique solution. This is a typical force redundant system [9][10][11][12][13]. One way to solve this problem is pseudoinverse solution. ...
Unlike general scissors, many commercial hairdressing scissors reflect ergonomic design with handles that provide users with comfort, minimizing fatigue and the risk of injury. However, there has not been a lot of prior research on quantitatively evaluating the merits of ergonomic design. This paper proposes a quantitative criterion to evaluate the performance of commercial hairdressing scissors. An experiment was conducted using several hairdressing scissors to establish the quantitative evaluation criterion. It was discovered that more fingers were involved than required to create a scissoring, and these fingers exerted antagonistic forces during the scissoring. Incorporating this property, a dynamic model of scissor mechanics was developed to analyze the characteristics of redundant finger forces, and a corresponding load distribution algorithm was derived. Three different types of scissor designs were compared through simulation. It was observed that the more ergonomic design was applied to the scissor, the less rotational kinetic energy was consumed. As a result, we propose rotational kinetic energy consumption as the quantitative evaluation criterion. The results of this research will be useful in designing specific scissor designs.
Compliant manipulators equipped with Variable Stiffness Actuation (VSA) possess the ability to safely interact with their environment and adapt to complex tasks. However, the tracking performance of such manipulators is significantly influenced by their intrinsic compliance and varying stiffness. This paper presents a robust control strategy for compliant manipulators equipped with Discrete Variable Stiffness Actuation (DVSA), aimed at enhancing tracking performance under both fixed and varying stiffness conditions. By compensating for nonlinear dynamics, joint coupling, frictions, stiffness variability and uncertainties through a Sliding Perturbation Observer (SPO), the proposed approach ensures robust and consistent performance, significantly outperforming traditional controllers. In fixed stiffness scenarios, the proposed controller achieves a reduction in energy consumption of up to 68.1% at the lowest stiffness and 75.5% at the highest stiffness, demonstrating superior efficiency. For abrupt stiffness transitions (lowest–highest–lowest), the proposed controller reduces energy consumption by up to 70.9% compared to traditional controllers. Additionally, it maintains smooth control input and precise tracking, avoiding the chattering and inefficiencies that traditional controllers typically exhibit. The SPO effectively estimates all system states and perturbation, compensating for nonlinearities, disturbances due to variable stiffness, and friction, enabling consistent trajectory tracking with minimal control effort. The proposed controller’s ability to adapt to varying stiffness levels without explicit parameter tuning highlights its robustness and practical viability. Simulation and experimental results validate its superior performance in reducing tracking error and energy consumption, particularly in scenarios where traditional controllers struggle to manage varying stiffness effectively.
