Powered exoskeletons are used to assist human walking, but it is inconvenient for a user to carry a bulky energy-supply system. During walking, human lower limbs accelerate and decelerate alternatively, during which period the human body does positive and negative work, respectively. Therefore, if the negative work performed during deceleration can be harnessed using some assisting device to then assist the acceleration movement of the lower limb, the total metabolic cost of the human body during walking can be reduced. In this work, an unpowered flexible lower-limb exoskeleton is proposed; it is worn in parallel to the lower limbs to assist human walking without consuming external electrical power. The flexible exoskeleton imitates the physiological structure of a human lower limb, consisting of elastic and damping components. When worn on the lower limb, the exoskeleton can partly replace the function of the lower limb muscles, which can scavenge kinetic energy during lower limb deceleration to assist the acceleration movement, so that the biomechanical power consumption can be reduced during walking. In addition to the walking assistance, the generator in the exoskeleton, serving as a damping component, can harvest kinetic energy to produce electricity for powering wearable electronics. A prototype of the flexible exoskeleton was developed, and experiments were carried out to validate the effectiveness. The experiments showed that the lower-limb exoskeleton could reduce the metabolic cost by 3.12% at the walking speed of 4.5 km/h, and a maximum electrical power of 6.47 W was generated at the walking speed of 5.1 km/h.

Conventional hydraulic dampers reduce vehicle vibration by converting the vibration energy into heat. In addition to wasting energy, the fixed damping characteristics of these dampers cannot adapt to different road conditions. As we know, a suspension with tunable damping provides a more comfortable ride. However, previous works regarding tunable regenerative dampers, which usually consist of a single generator, have some shortcomings, including wasted energy and a limited range of tunable damping. With these problems in mind, a new design principle with multiple controlled transducers is discussed in this paper. By controlling the number of switched-on transducers and adjusting the value of the external resistance, the damping characteristics can be fine-tuned according to the requirements. With this new design principle, a regenerative damper can not only tune the damping behavior over a broader range but also harvest as much vibration energy as possible. The design principle was verified by building and testing two different prototypes. The experimental results showed that these two dampers could achieve nearly linear turning of the damping coefficient and harvest more electrical power from vibrations than other type of energy-harvesting dampers.

Purpose: The purpose of this paper is to design a lower limb exoskeleton to enhance hemiplegic patient’s muscle strength and help the affected side return to normal gait after a long period of training. Design/methodology/approach: A wire rope-driven exoskeleton that combines rigid bracket and flexible driven method was presented to assist the patients with rehabilitative walking training. By using three noncontact cameras, the patient’s gait was captured and the target trajectory of the affected side was analyzed. Meanwhile, a controlling strategy of the affected side, which mimics the gait of the healthy side, was developed to help hemiplegic patients with varying degrees of hemiplegic gait obtain personalized walking rehabilitation training. Findings: The results show that the hemiplegic gait of hip excessive abduction and strephenopodia was prevented. After wearing the exoskeleton, the movement trajectories of both sides of the lower limb were approximately identical. Based on the controlling strategy, the exoskeleton can correct the impaired gait and provide assistance for patients during walking. The exoskeleton has great benefits in walking rehabilitation training for hemiplegic patients. Originality/value: This work improves the efficiency of the patient’s individualized training in the room. The presented exoskeleton provides great benefits in walking rehabilitation training for hemiplegic patients.

Robot-assisted therapy offers a promising approach to rehabilitation, particularly for severely to moderately impaired stroke patients. This paper presents the Dual-Arm End-Effector-Based Rehabilitation Robot (DEREROB), which is a robotic system for upper limb physiotherapy including two co-operating robot arms. With this configuration, the robot arms of DEREROB are connected to the patient's upper arm and forearm respectively, which mimics the therapist's arms to provide the rehabilitation treatment. The kinematics model has been framed by D-H method and kinematics simulation has been carried out to verify that the DEREROB can assist the affected arm move in 3D space.