Mohammad Rahman

• PhD
• Professor (Associate) at University of Wisconsin–Milwaukee

Robotic-assisted therapy is an increasingly vital approach for upper-limb rehabilitation, offering consistent, high-intensity training critical to neuroplastic recovery. However, current control strategies often lack robustness against uncertainties and external disturbances, limiting their efficacy in dynamic, real-world settings. Addressing this...

Each year, around 15 million people globally, including 795,000 Americans, experience a stroke. Nearly half of stroke survivors face persistent upper limb motor impairments, limiting daily activities and quality of life. This underscores the need for early, intensive, and function-focused rehabilitation. This study explores the effectiveness of int...

Additive manufacturing (3D printing) has revolutionized the production of complex geometries; however, the mechanical properties of 3D-printed parts, particularly their susceptibility to failure along the Z-axis, remain a critical limitation. This study presents a simple yet novel post-processing method, commonly used in other applications, to enha...

Background Robot-assisted telerehabilitation (RAT) is an emerging field that integrates digital health technologies with robotics to deliver remote therapy, offering significant potential to overcome geographical and accessibility barriers in stroke rehabilitation. This approach holds great promise for enhancing upper limb (UL) recovery in stroke s...

The increasing prevalence of upper limb dysfunctions due to stroke, spinal cord injuries, and multiple sclerosis presents a critical challenge in assistive technology: designing robotic arms that are both energy-efficient and capable of effectively performing activities of daily living (ADls). this challenge is exacerbated by the need to ensure the...

This paper addresses the challenge of precise control and robust trajectory tracking for Four Mecanum Wheeled Mobile Robots (FMWMR) operating in environments where time-sensitive responses are critical and external conditions may vary. Traditional control approaches often fall short due to slow convergence rates and limited resilience to disturbanc...

In this paper, we develop a virtual vehicle scheme to solve the coordination control problem under denial-of-service (DoS) attacks for heterogeneous vehicles. This system includes an unmanned surface vessel (USV) in distress, sharing kinematic data, and a helicopter receiving data from the latter through wireless communication. Specifically, we car...

The increasing number of individuals with disabilities—over 61 million adults in the United States alone—underscores the urgent need for technologies that enhance autonomy and independence. Among these individuals, millions rely on wheelchairs and often require assistance from another person with activities of daily living (ADLs), such as eating, g...

Recently, there has been widespread and vital adoption of flexible manipulators due to their increased prevalence. This is attributed to the growing demand for flexibility in various tasks like refueling operations, inspections, and maintenance activities. Nevertheless, these robots are under-actuated systems characterized by a nonlinear behavior a...

In this paper, a new approach for formation‐containment control with prescribed performances is introduced for heterogeneous autonomous vehicles involving a cluster of leader unmanned aerial vehicles (UAVs) and follower unmanned surface vessels (USVs). We introduce a two‐layer distributed control system: The upper layer focuses on guiding the UAVs...

Background The current study explores the integration of a motor imagery (MI)-based BCI system with robotic rehabilitation designed for upper limb function recovery in stroke patients. Methods We developed a tablet deployable BCI control of the virtual iTbot for ease of use. Twelve right-handed healthy adults participated in this study, which invo...

The increasing prevalence of upper and lower extremity (ULE) functional deficiencies presents a significant challenge, as it restricts individuals’ ability to perform daily tasks independently. Robotic devices are emerging as assistive devices to assist individuals with limited ULE functionalities in activities of daily living (ADLs). While assisti...

A significant number of individuals in the United States use assistive devices to enhance their mobility, and a considerable portion of those who depend on such aids require assistance from another individual in performing daily living activities. The introduction of robotic grippers has emerged as a transformative intervention, significantly contr...

According to the World Health Organization, hundreds of individuals commence wheelchair use daily, often due to an injury such as spinal cord injury or through a condition such as a stroke. However, manual wheelchair users typically experience reductions in individual community mobility and participation. In this review, articles from 2017 to 2023...

In this article, we present a new fixed-time observer (FTO) with time delay estimation (TDE)-based model-free fixed-time sliding mode for the problem of robust walking of the NAO robot. The proposed technique ensures convergence in fixed time, regardless of initial conditions, thereby enhancing both convergence speed and robustness. This method all...

Current implementations of leader-follower systems in multi-robot environments typically separate path planning and formation control, often leading to inefficiencies in execution speed, path quality, and system stability. These systems rely on complex control strategies that struggle to adapt to dynamic and challenging environments, resulting in s...

Upper limb dysfunction (ULD) is common following a stroke, spinal cord injury, trauma, and occupational accidents. Post-stroke patients with ULD need long-term assistance from therapists for their rehabilitation, which generally occurs at the hospital or outpatient clinic. Physical therapists are unavailable because of geographical, financial, and...

Objective Low-density lipoprotein-cholesterol (LDL-C) remains a clinically important cholesterol target in primary prevention of atherosclerotic cardiovascular disease. The present study aimed to assess the practical differences among three equations utilized for the estimation of LDL-C: the Friedewald, the Martin/Hopkins, and the NIH equation 2....

Several recent studies have indicated that upper extremity injuries are classified as a top common workplace injury. Therefore, upper extremity rehabilitation has become a leading research area in the last few decades. However, this high number of upper extremity injuries is viewed as a challenging problem due to the insufficient number of physioth...

This study addresses two issues about the interaction of the upper limb rehabilitation robot with individuals who have disabilities. The first step is to estimate the human's target position (also known as TPH). The second step is to develop a robust adaptive impedance control mechanism. A novel Non-singular Terminal Sliding Mode Control combined w...

This research shows the development of a teleoperation system with an assistive robot (NAO) through a Kinect V2 sensor, a set of Meta Quest virtual reality glasses, and Nintendo Switch controllers (Joycons), with the use of the Robot Operating System (ROS) framework to implement the communication between devices. In this paper, two interchangeable...

Recent technological advances enable gripper-equipped robots to perform many tasks traditionally associated with the human hand, allowing the use of grippers in a wide range of applications. Depending on the application, an ideal gripper design should be affordable, energy-efficient, and adaptable to many situations. However, regardless of the numb...

The number of individuals with upper or lower extremities dysfunction (ULED) has considerably increased in the past decades resulting in a high economic burden the families and society. Individuals with ULEDs require assistive robots to fulfill all their activities of daily living (ADLs). Thus, this research presents an objective function for base...

The number of individuals with upper or lower extremities dysfunction (ULED) has considerably increased in the past few decades, resulting in a high economic burden for their families and society. Individuals with ULEDs require assistive robots to fulfill all their activities of daily living (ADLs). However, a theory for the optimal design of assis...

Being an emerging technology, robotic manipulation has encountered tremendous advancements due to technological developments starting from using sensors to artificial intelligence. Over the decades, robotic manipulation has advanced in terms of the versatility and flexibility of mobile robot platforms. Thus, robots are now capable of interacting wi...

Research Objectives To develop a more interactive method of at-home upper limb rehabilitation - utilizing the HoloLens 2 - that allows therapists to provide rehab exercises and track their patients' progress by recording the patients' upper limb joint angles. Design Experimental study. Setting This experiment was set in a laboratory (BioRobotics...

Research Objectives Two assistive robotic prototype devices were designed to assist people with upper extremity disorders in performing Activities of Daily Living (ADL). This study aimed to compare the functionality and performance of the 2-finger gripper and the 3-finger gripper while performing ADL tasks. Design Experimental study. Setting In t...

Research Objectives This study aimed (1) to investigate the hierarchical properties of FMA-LE and Brunnstrom stages, and (2) to develop a functional staging, a graphical plot, of FMA-LE and its relationships to low (0–21), high (22–34) FMA-LE cut-off scores. Design Secondary analysis of cross-sectional data. Setting Outpatient rehabilitation sett...

Research Objectives The aim is to develop a novel telerehabilitation system to deliver robot-assisted rehabilitation using IIoT (Industrial Internet of Things) PTC ThingWorx, and AR (Augmented Reality) Vuforia Studio platforms. Design Experimental Study. Setting In the BioRobotics Lab. Participants Three healthy participants, age: 23–35 years, h...

Research Objectives This study aimed (1) to investigate the hierarchical properties of FMA-UE and Brunnstrom stages, and (2) to develop a functional staging, a graphical plot, of FMA-UE and its relationships to severe (0–28), moderate (29–42), and mild (43–66) FMA-UE cut-off scores. Design Secondary analysis of cross-sectional data. Setting Outpa...

Research Objectives This research proposes a telerehabilitation framework with a developed desktop-mounted rehabilitation robot (DMRbot) and PTC's Industrial Internet of Things (IIoT) platform to remotely provide home-based passive rehabilitation therapies to individuals with upper limb dysfunctions. Design Experimental study. Setting In the BioR...

Research Objectives The data management system was designed to integrate an individual's profile to track their progress and receive the recommended advice from the expert. Design Experimental study. Setting In the Biorobotics Lab. Participants Ten healthy participants (Mean age 27.86 years old). Interventions An assistive robotic device perfor...

Research Objectives The bone mineral density (BMD) reflects bone health and is associated with the risk of developing osteoporotic fractures. This study aimed to examine the trends in BMD values in US 6-80 years old, and the changes in BMD values between 2005 and 2020. Design This is a cross-sectional observational study. Setting General communit...

Research Objectives Upper limb dysfunctions (ULD) are common following a neurological insult. Passive range of motion (PROM) exercise of the affected extremity is one of the critical components of current rehabilitation plans of care when treating these patients. Robot-aided rehabilitation is a promising technology for this and comes with the added...

The advancements in mixed reality (MR) technology in recent years have provided us with excellent prospects for creating novel approaches to supplement conventional physiotherapy to maintain a sufficient quantity and quality of rehabilitation. The use of MR systems to facilitate patients’ participation in intensive, repetitive, and task-oriented pr...

In this article, a robust adaptive impedance control based on the modified function approximation technique, and augmented with a novel integral nonsingular terminal sliding mode control, is proposed for a surgical haptic system. The haptic device is maneuvered by surgeons, whereby the mode of action, motion path, and haptic dynamics are rendered a...

Significant advancements in contemporary telemedicine applications enforce the demand for effective and intuitive telerehabilitation tools. Telerehabilitation can minimize the distance, travel burden, and costs between rehabilitative patients and therapists. This research introduces an interactive novel telerehabilitation system that integrates the...

Background: Elevated levels of low-density lipoprotein cholesterol (LDL-C) are associated with an increased risk of coronary heart disease. Objectives: We described LDL-C distributions across the age span and compared the trends in three distinct cross-sectional surveys during 2007-2010, 2011-2014, and 2015-2018. Methods: This is an observational s...

Geriatric disorders, strokes, spinal cord injuries, trauma, and workplace injuries are all prominent causes of upper limb disability. A two-degrees-of-freedom (DoFs) end-effector type robot, iTbot (intelligent therapeutic robot) was designed to provide upper limb rehabilitation therapy. The non-linear control of iTbot utilizing modified sliding mod...

Artificial limbs are new robotic devices created to help stroke victims in the rehabilitation process. In this article, we focus our work on applying passive, active or assistive control strategies to provide a physical assistance and rehabilitation by a 7-degree-of-freedom exoskeleton robot with nonlinear uncertain dynamics and unknown bounded ext...

Age-related problems, including cardiovascular diseases such as stroke, are among the most common causes of disability worldwide. Stroke causes musculoskeletal disorders, including motor deficits in the upper and lower limbs. Rehabilitation therapies are considered the most effective treatment for promoting functional recovery. Rehabilitation robot...

Throughout the last decade, many assistive robots for people with disabilities have been developed; however, researchers have not fully utilized these robotic technologies to entirely create independent living conditions for people with disabilities, particularly in relation to activities of daily living (ADLs). An assistive system can help satisfy...

Patients with upper and lower extremity dysfunction suffer from a non-independent life. They depend on other people to do their daily activities. Hence, the importance of assistive robots in their lives and the design challenges of these robots. The assistive robots must be capable of reaching and handling different spaces and objects. Thus, the un...

Robots are used today in many different fields and for many different tasks. However, they quickly reach their limits without a "sense of sight," especially when working directly with humans as assistive robots. Applications that require sophisticated intelligence must work under flexible conditions that are usually not feasible without vision syst...

The amputation of a limb is a disabling condition that affects millions of people worldwide. This situation bolsters the necessity of devices that help the integration of those individuals into society. However, the design of such mechanisms faces many issues for their simple implementation, such as the reduced space to add actuators while maintain...

This paper investigates the localization and circumnavigation problem for a group of underactuated surface vessels (USVs). In particular, the USVs collaboratively locate an unknown moving target and then circumnavigate it isometrically with desired spacing angle and velocity. In this strategy, the target information is assumed to be known to only s...

Background: Applications of robotics in daily life are becoming essential by creating new possibilities in different fields, especially in the collaborative environment. The potentials of collaborative robots are tremendous as they can work in the same workspace as humans. A framework employing a top-notch technology for collaborative robots will s...

Upper limb dysfunctions (ULD) are common following a stroke. Annually, more than 15 million people suffer a stroke worldwide. We have developed a 7 degrees of freedom (DoF) exoskeleton robot named the smart robotic exoskeleton (SREx) to provide upper limb rehabilitation therapy. The robot is designed for adults and has an extended range of motion c...

Research Objectives In robot-aided rehabilitation of post-stroke patients with upper limb impairment, robotic device must allow patient's effort in performing exercises. To estimate such effort, user's force exerted on robotic device can be used during active exercises. To validate use of force exerted by user/wearer by comparing with EMG signals a...

In this paper, a walking algorithm of a biped robot with unknown dynamics has been addressed by proposing a new adaptive control based on the Modified Function Approximation Technique (MFAT) augmented with backstepping control, using state feedback and output feedback. The classical ZMP, the preview controller on the 3- Dimensional Linear Inverted...

Background Applications of robotics in daily life are becoming essential by creating new possibilities in different fields, especially in the collaborative environment. The potentials of collaborative robots are tremendous as they can work in the same workspace as humans. A framework employing a top-notch technology for collaborative robots will su...

BACKGROUND Applications of robotics in daily life are becoming essential by creating new possibilities in different fields, especially in the collaborative environment. The potentials of collaborative robots are tremendous as they can work in the same workspace as humans. A framework employing a top-notch technology for collaborative robots will su...

Universal joints are required to achieve linear motion in the design of linear-translational-parallel-robots (LTPR). A usual practice among researchers is to assume that the angular velocity of a link attached to a universal joint is perpendicular to it. Although this assumption is intuitive, this research proves analytically and experimentally the...

As many factors that can be attributed to a high-performance robotic system and with increasing demand for robotic application in automation or as assistive devices, research in this area has received much attention. Robot manipulation is one of the vital components of the industrial or assistive robotic system. The utilization of various vision-ba...

Recent statistics reveal that the number of individuals with upper or lower extremity dysfunctions has increased alarmingly. It is estimated that approximately 3.3 million Americans use a wheelchair, with an expected 2 million new wheelchair users every year. To assist powered wheelchair users with limited upper limb function, we have been explorin...

It is estimated that nearly 16 million people are affected by stroke worldwide every year. Among them, more than 60% of individuals suffer from upper limb dysfunction. Robotic rehabilitation therapy has been proven to improve these individuals' motor ability and positively affect their recovery. In this research, Desktop-Mounted Rehabilitation Robo...

Background Building control architecture that balances the assistive manipulation systems with the benefits of direct human control is a crucial challenge of human–robot collaboration. It promises to help people with disabilities more efficiently control wheelchair and wheelchair-mounted robot arms to accomplish activities of daily living. Methods...

Steady-state Visually Evoked Potential (SSVEP) based Electroencephalogram (EEG) signal is utilized in brain-computer interface paradigms, diagnosis of brain diseases, and measurement of the cognitive status of the human brain. However, various artifacts such as the Electrocardiogram (ECG), Electrooculogram (EOG), and Electromyogram (EMG) are presen...

In this paper, a new adaptive control strategy, based on the Modified Function Approximation Technique, is proposed for a manipulator robot with unknown dynamics. This novel strategy benefits from the backstepping control approach and the use of state and output feedback. Unlike the conventional Function Approximation Technique approach, the use of...

Home-based hand rehabilitation has excellent potential as it may reduce patient dropouts due to travel, transportation, and insurance constraints. Being able to perform exercises precisely, accurately, and in a repetitive manner, robot-aided portable devices have gained much traction these days in hand rehabilitation. However, existing devices fall...

Research Objectives To Implement Human Computer Interface (HCI) with digital image processing for a new approach to control assistive robots. Design Experimental Study. Setting In UWM BioRobotics Lab. Participants Healthy participants. Interventions Assistive robot control for daily living activities(Eating, Picking/Placing Objects), Nose track...