scholarly journals Switching Control of Impedance Control/Torque Control for Human-Robot Cooperative Task : Human-robot cooperative bolting task

2003 ◽  
Vol 2003 (0) ◽  
pp. 56
Author(s):  
K. Kawamura ◽  
A. Sakamoto ◽  
T. Tsumugiwa ◽  
R. Yokogawa ◽  
K. Hara
Keyword(s):  
Impedance Control ◽  
Switching Control ◽  
Torque Control ◽  
Control Torque

Myoelectric Torque Control of an Active Transfemoral Prosthesis During Stair Ascent

2011 ◽  
Author(s):  
Carl D. Hoover ◽  
Kevin B. Fite ◽  
George D. Fulk ◽  
Donald W. Holmes
Keyword(s):  
Impedance Control ◽  
Torque Control ◽  
Motion Capture Data ◽  
Clinical Tests ◽  
Joint Kinetics ◽  
Set Point ◽  
Stair Ascent ◽  
Normal Gait ◽  
Stiffness And Damping ◽  
Transfemoral Prosthesis

This paper presents experimental results of a myoelectric impedance controller designed for reciprocal stair ascent with an active-knee powered transfemoral prosthesis. The controller is modeled from non-amputee (normal) motion capture data, estimating knee torque with a linear two-state (stance/swing) impedance control form that includes proportional myoelectric torque control. The normal gait model is characterized by small stiffness and damping in both stance and swing, a low angle set-point in stance, a high angle set-point in swing, and proportional myoelectric control in stance but not swing. Clinical tests with a single unilateral transfemoral amputee indicate good performance of the controller; however, subject feedback suggests a reduction in the extensive myoelectric torque parameter and the need for constant, balanced myoelectric torque parameters in both stance and swing. Average prosthesis knee joint kinetics from a stairwell test using the amputee-tuned controller compare favorably with non-amputee gait data.

scholarly journals Cerebellar ataxia impairs modulation of arm stiffness during postural maintenance

2013 ◽  
Vol 110 (7) ◽  
pp. 1611-1620 ◽  
Author(s):  
Tricia L. Gibo ◽  
Amy J. Bastian ◽  
Allison M. Okamura
Keyword(s):  
Cerebellar Ataxia ◽  
Motor Coordination ◽  
Matched Control ◽  
Impedance Control ◽  
Torque Control ◽  
Joint Torque ◽  
Motor Deficits ◽  
Control Subjects ◽  
Impedance Modulation ◽  
Cerebellar Damage

Impedance control enables humans to effectively interact with their environment during postural and movement tasks, adjusting the mechanical behavior of their limbs to account for instability. Previous work has shown that people are able to selectively modulate the end-point stiffness of their arms, adjusting for varying directions of environmental disturbances. Behavioral studies also suggest that separate controllers are used for impedance modulation versus joint torque coordination. Here we tested whether people with cerebellar damage have deficits in impedance control. It is known that these individuals have poor motor coordination, which has typically been attributed to deficits in joint torque control. Subjects performed a static postural maintenance task with two different types of directional force perturbations. On average, patients with cerebellar ataxia modified stiffness differentially for the two perturbation conditions, although significantly less than age-matched control subjects. Thus cerebellar damage may impair the ability to modulate arm impedance. Surprisingly, the patients' intact ability to generally alter their limb stiffness during the postural task (albeit less than age-matched control subjects) improved their movement performance in a subsequent tracing task. The transfer of stiffness control from the static to the movement task may be a strategy that can be used by patients to compensate for their motor deficits.

Interaction Torque Control by Impedance Control of Space Robots

SIMULATION ◽  
2009 ◽  
Vol 85 (7) ◽  
pp. 451-459 ◽  
Author(s):  
Pushparaj Mani Pathak ◽  
Amalendu Mukherjee ◽  
Anirvan Dasgupta
Keyword(s):  
Impedance Control ◽  
Torque Control ◽  
Space Robots ◽  
Interaction Torque

Maximizing Wind Turbine Energy Capture via Extremum Seeking Control

2008 ◽  
Author(s):  
Justin Creaby ◽  
Yaoyu Li ◽  
John E. Seem
Keyword(s):  
Wind Turbine ◽  
Torque Control ◽  
Extremum Seeking ◽  
Control Torque ◽  
Pass Filter ◽  
Extremum Seeking Control ◽  
Energy Capture ◽  
Variable Speed Wind Turbine ◽  
Speed Up ◽  
High Pass

Maximizing wind turbine energy capture has become an important issue as more turbines are installed in low wind areas. This paper investigates the application of extremum seeking control (ESC) to maximizing the energy capture of variable speed wind turbine. The optimal control torque and pitch angle are searched via ESC based on the measurement of output power. The advantage is the independency from accurate wind measurement. Simulation has been conducted on FAST for a wind turbine dynamic model, under uniformly steady wind, stair-case wind speed variations, and turbulence wind. The simulation results indicated that the captured power increased by up to 4% over the standard torque control. Anti-windup ESC was then applied to overcome the actuation saturation which may disable the ESC process. Finally, the ESC with high-pass filter input resetting was applied to speed up the transient under abrupt change of wind.

Gait planning and control of quadruped crawling robot on a slope

2019 ◽  
Vol 47 (1) ◽  
pp. 12-22
Author(s):  
Peng Wang ◽  
Chunxiao Song ◽  
Xiaoqiang Li ◽  
Peng Luo
Keyword(s):  
Position Control ◽  
Impedance Control ◽  
Switching Control ◽  
Gait Planning ◽  
Content Type ◽  
Planning And Control ◽  
Smooth Switching ◽  
The Stability ◽  
And Control ◽  
Soft Control

Purpose The gait planning and control of quadruped crawling robot affect the stability of the robot walking on a slope. The control includes the position control in the swing phase, the force control in the support phase and the switching control in the force/position switching. To improve the passing ability of quadruped crawling robot on a slope, this paper aims to propose a soft control strategy. Design/methodology/approach The strategy adopts the statically stable crawling gait as the main gait. As the robot moves forward, the position/force section switching control is adopted. When the foot does not touch the ground, the joint position control based on the variable speed PID is performed. When the foot touches the ground, the position-based impedance control is performed, and a fuzzy multi-model switching control based on friction compensation is proposed to achieve smooth switching of force and position. Findings The proposed method offers a solution for stable passage in slope environment. The quadruped crawling robot can realize smooth switching of force/position, precise positioning in the swing process and soft control of force in the supporting phase. This fact is verified by simulation and test. Originality/value The method presented in this paper takes advantage of minimal tracking errors and minimal jitters. Simulations and tests were performed to evaluate the performance.

scholarly journals Robotic Comanipulation With Active Impedance Control

2009 ◽  
Author(s):  
Rui Cortesa˜o ◽  
Brian Zenowich ◽  
Rui Arau´jo ◽  
William Townsend
Keyword(s):  
Impedance Control ◽  
Torque Control ◽  
Task Space ◽  
Control Techniques ◽  
Time Control ◽  
Computed Torque Control ◽  
Position Data ◽  
Active Impedance ◽  
Design Experiments ◽  
Computed Torque

The paper presents active impedance control for robotic comanipulation tasks, enabling virtual contact interactions. Computed torque control in the task space powered by multiple-output active observers (AOBs) is proposed, enhancing haptic perception. Forces and force derivatives are artificially measured from position data around an equilibrium point that can move with time. Control techniques to deal with critical impedances are introduced, taking into account the noise distribution along the system. Stochastic design is discussed. A dynamic model of the redundant lightweight 7-DOF WAM™ arm is derived and evaluated, playing a key role in the control design. Experiments for small and high impedances are presented, highlighting merits and limitations of the approach. A comparative study between active and non-active impedance control is made.

Position-Based Fractional-Order Impedance Control of a 2 DOF Serial Manipulator

Robotica ◽  
2021 ◽  
pp. 1-15
Author(s):  
Selçuk Kizir ◽  
Ali Elşavi
Keyword(s):  
Fractional Order ◽  
Position Control ◽  
Robot Manipulator ◽  
Impedance Control ◽  
Torque Control ◽  
Control Scheme ◽  
Absorption Performance ◽  
And Performance ◽  
Comparison Of The Results ◽  
Robotic Tasks

SUMMARY Impedance control is one of the interaction and force control methods that has been widely applied in the research of robotics. In this paper, a new position-based fractional-order impedance control scheme is proposed and applied to a 2 DOF serial manipulator. An RR robot manipulator with full arm dynamics and its environment were designed using Matlab/Simulink. The position control of the manipulator was utilized based on computed torque control to cancel out the nonlinearities existing on the dynamic model of the robot. Parameters of classical impedance controller (CIC) and proposed fractional-order impedance controller (FOIC) were optimized in order to minimize impact forces for comparison of the results in three conditions. In CIC condition: three constant parameters of the impedance controller were optimized: in Frac_λμ condition: Only non-integer parameters of the FOIC were re-optimized after the parameters in CIC had been accepted, and in Frac_all condition: all parameters of the FOIC were re-optimized. In order to show the effectiveness of the proposed method, simulations were conducted for all cases and performance indices were computed for the interaction forces. Results showed that impacts were reduced with an improvement of 26.12% from CIC to Frac_ λμ and an improvement of 47.21% from CIC to Frac_all. The proposed scheme improves the impedance behavior and robustness showing better impact absorption performance, which is needed in many challenging robotic tasks and intelligent mechatronic devices.

Sign in / Sign up

Export Citation Format

Share Document