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This paper presents a novel Differential Modular Robot Joint (DMRJ), which has high payload capability and low weight. The ratio between the output torque and the reducer's weight is 178.3 Nm/kg, which is the highest value we have known. The DMRJ is designed modularly for high payload tasks and can be attached to robots as arms or legs. Two high power DC brush motors are applied to drive the differential...
A highly integrated joint controller using in a humanoid robot arm has been developed in the paper. The joint controller is highly integrated with position sensors — the hall sensors, the magnetic sensor and the photoelectrical sensor, the torque sensors, the temperature sensor and so on. Besides, it can control and drive the motor in PWM and SVPWM modes. What is more, the joint controller has been...
Eccentric paddle mechanism based on epicyclic gear mechanism (ePaddle-EGM) is a novel locomotion mechanism designed for amphibious robot. The epicyclic gear mechanism is the key component of ePaddle-EGM to perform multiple gaits. In this paper, efficiency of the epicyclic gear mechanism is analyzed. Via the virtual power flow, we characterize how the efficiency relates with the velocity ratio and...
This paper investigates the performance of impedance control utilizing an inner loop PI torque controller. Stiffness and damping shaping vary within a specified range of values. The impedance control problem is formulated taking into account a specified range of stiffness and damping parameters. The analysis and design is carried out in discrete time. Stability, passivity, impedance emulation as well...
Compared with a single-arm space robot, a dual-arm space robot has much more dexterity and flexibility, and is capable to complete more complex tasks. The on-orbit capturing and manipulation of a target is the key of the on-orbit servicing mission. After the target is captured by the two arms, a compounded system is formed. The two arms connect the robotic base to the target, and a closed kinematics...
Though balancing is a fundamental part of human walking, it has been a challenging topic for bipedal robot. Compared to the versatile strategies of handling disturbances of human, current bipedal robots possess limited skills of managing external disturbances. Among them the capabilities of push recovery and maintaining balance are obviously of prior importance for a bipedal robot to walk in an unknown...
Accurate force/torque (F/T) information is essentially important for a robot manipulator to regulate the contact forces and torques exerted on its tool (end-effector). For a manipulator with mounted F/T sensor, the tool and the F/T sensor are connected to the manipulator via some components, of which many parameters such as mounting errors and component's weight are unknown. As a result, the forces...
As the impedance profiles of the human joints vary substantially during motion, the employment of variable impedance systems into exoskeletons, orthoses and prostheses that will be able to produce human-like mechanics could have significant benefits. In this direction, this manuscript presents a generic technique to estimate active joint stiffness based on an EMG-driven musculoskeletal model whose...
This paper addresses a problem of locomotion control of a snake-like robot. The discontinuity of the input signal during transition of locomotion is not desirable which may cause a large sliding and slippage. To overcome this problem, a method that produce a smooth transition of the body shape of a snake-like robot is introduced by adopting CPG-based control. Body shape transition is important for...
This paper presents a design method to determine the output ratio of a differential mechanism, which is installed in an in-pipe robot with three underactuated parallelogram crawler modules. The crawler module can automatically shift its shape to a parallelogram when encountering with obstacles. To clarify the requirements for the mechanism, two outputs of each crawler mechanism (torque of the arms...
It is challenging to design a humanoid robot control framework that maintains high-level motion performance in an unknown environment as this requires complicated sensing capabilities and time-consuming process. On the other hand, basic autonomous motion control in joint space is relatively easier and faster to fulfil dynamic tasks. Based on modeling of human muscles, this paper proposes a biological...
Optimal point-to-point motion planning of heavy-duty industry robot was critical between two points in the prescribed time. The dynamic modeling was derived though Lagrange formulation and Spong model; then based on the Pontryagin's minimum principle, optimal point-to-point motion planning problem was constructed considering the gravity effect. Indirect method integration with homotopy mapping was...
In order to investigate the feasibility of integrating functional electrical stimulation (FES) with robot-based rehabilitation training, this paper proposes an FES-assisted training strategy combined with impedance control for our self-made exoskeleton lower limb rehabilitation robot. This control strategy is carried out in a leg press task. Through impedance control, an active compliance of the robot...
The ship podded SSP(Siemens-Schottel-Propulsor, SSP) propulsion motor is a multivariable complex nonlinear plant with strong coupling and time-varying parameters. It is hard to reconcile the contradiction between the performance of anti-interference and response speed by self-adapt PI vector control during rough sea or navigation in harbor. It is difficult to obtain the system parameters accurately...
Different from the traditional using method of one-input-one-output in planetary gear reducer, a concept of one-input-two-output is proposed to drive an underactuated finger. A finger consisting of three degrees of freedom, is driven by two actuators. MP joint is driven by one actuator while PIP and DIP joints are driven by another actuator with power distribution by a planetary gear reducer. When...
The realization of natural, fast and versatile motions for bipedal robots is still a challenge. As one approach to enhance the performance of bipedal robots, actuation with high backdrivability, high power-to-weight ratio as well as high torque is required. In this paper, a new mechanism of knee joint with variable reduction ratio adaptive to load is proposed to improve the capability of actuation...
Traditionally, discrete robot's performance in flexibility and obstacle avoidance is not very outstanding, while continuum robot cannot load much and its motion space is limited. In this paper, a new robot with hybrid joints was designed based on the two kinds of robots mentioned above. First, the connection mode between discrete and continuum joints was analyzed. It was found that when the axis of...
Lower extremity exoskeletons can improve human strength and endurance with a pair of wearable robotic legs that support a payload. This paper summarizes the biomimetic design and biomechanical analysis of a novel 15-DOF (degree of freedom) lower extremity exoskeleton. The selection of the DOF, critical parameter design, and initial performance simulation are discussed. To provide a basis and guidance...
In this article, design of bionic quadruped, mainly focusing on leg design, is given and force analysis of the mechanism is calculated and simulated. To better improve the design, force on sole and torque on joints should be diminished to increase the mobility and capacity of the robot. Therefore, a design method based on biomechanics and bionic control strategy is proposed for this quadruped robotic...
Rotary-percussive Drill (RPD) has been widely employed in extraterrestrial exploration as a main drilling and sampling device. Percussive mechanism, as an inevitable part of RPD, is commonly utilized to exert percussion onto drill stem to improve drilling performance once hard rock is encountered. However, since driving resource provided by the probe is limited in lunar exploration, outputs of percussive...
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