scholarly journals Impedance Control Approach on Leg Motion Speed Variation on Soft Surface Interaction

2018 ◽  
Vol 7 (4.27) ◽  
pp. 16 ◽  
Author(s):  
Wan Mohd Nafis Wan Lezaini ◽  
Addie Irawan ◽  
Akhtar Razul Razali
Keyword(s):  
Force Feedback ◽  
Impedance Control ◽  
Dynamic Control ◽  
Surface Displacement ◽  
Legged Robot ◽  
Foot Placement ◽  
Control Approach ◽  
Speed Variation ◽  
Soft Surface ◽  
Leg Motion

This article presents the leg speed variation control using impedance control approach on soft surface displacement motion. One of the challenging fields of designing a legged robot that can be equipped with adaptation ability is it dynamic control which majorly involved in interaction with the environment. Numerous researchers have been widely implemented impedance control as dynamic interaction but less emphasized in adapting soft terrain. Most of the impedance control implementation on the legged robot on rough terrain emphasized on position changes, and it may not practical for legged robot navigate on the soft terrain. Soft terrain contains different ground stiffness and medium viscosities. Thus, this study has taken the initiative to propose a speed variation control on a robot’s leg by using a force-based impedance control approach to increase the leg energy exchanges specifically on foot placement. The proposed control was validated in actual robot’s leg, and performances show that the energy in the leg increases as the velocity of leg motion increase due to increase in force feedback while maintaining the shape of the leg motion.  

Learning peg-in-hole assembly using Cartesian DMPs with feedback mechanism

2020 ◽  
Vol 40 (6) ◽  
pp. 895-904
Author(s):  
Nailong Liu ◽  
Xiaodong Zhou ◽  
Zhaoming Liu ◽  
Hongwei Wang ◽  
Long Cui
Keyword(s):  
Force Feedback ◽  
Impedance Control ◽  
Dynamic Performance ◽  
Feedback Mechanism ◽  
Learning From Demonstration ◽  
Content Type ◽  
Control Approach ◽  
Cartesian Space ◽  
Compliant Behavior ◽  
Dynamic Movement Primitives

Purpose This paper aims to enable the robot to obtain human-like compliant manipulation skills for the peg-in-hole (PiH) assembly task by learning from demonstration. Design/methodology/approach A modified dynamic movement primitives (DMPs) model with a novel hybrid force/position feedback in Cartesian space for the robotic PiH problem is proposed by learning from demonstration. To ensure a compliant interaction during the PiH insertion process, a Cartesian impedance control approach is used to track the trajectory generated by the modified DMPs. Findings The modified DMPs allow the robot to imitate the trajectory of demonstration efficiently and to generate a smoother trajectory. By taking advantage of force feedback, the robot shows compliant behavior and could adjust its pose actively to avoid a jam. This feedback mechanism significantly improves the dynamic performance of the interactive process. Both the simulation and the PiH experimental results show the feasibility and effectiveness of the proposed model. Originality/value The trajectory and the compliant manipulation skill of the human operator can be learned simultaneously by the new model. This method adopted a modified DMPs model in Cartesian space to generate a trajectory with a lower speed at the beginning of the motion, which can reduce the magnitude of the contact force.

Control System Design of 1 DOF Kinesthetic Interface

2015 ◽  
Vol 799-800 ◽  
pp. 1158-1165
Author(s):  
Paolo Righettini ◽  
Alessandro Gotti ◽  
Mattia Rossetti ◽  
Roberto Strada
Keyword(s):  
Closed Loop ◽  
Force Feedback ◽  
Impedance Control ◽  
Laboratory Research ◽  
Control System Design ◽  
Admittance Control ◽  
Control Approach ◽  
Dynamic Accuracy ◽  
High Dynamic ◽  
Natural Dynamics

The aim of this work is to investigate the performance of closed-loop impedance control in the case of a kinesthetic interface, more precisely to propose this control approach even for devices in which the natural dynamics of the system are relevant. This characteristic can be found in an industrial scenario where commercial components are generally used; hence the system can't be optimized as conversely occurs in a laboratory/ research environment where custom components are generally developed. It is shown that it is possible to guarantee a high dynamic accuracy using the closed-loop impedance control with force feedback and model feedforward. Therefore this approach is suggested as a valid alternative of the most diffused admittance control. The device implemented for the tests and the obtained results are described below.

Active Vibration Isolation for A Parallel Wheel-legged Robot Based on Dynamic Model

2020 ◽  
Author(s):  
Fei Guo ◽  
Shoukun Wang ◽  
Binkai Yue ◽  
Junzheng Wang
Keyword(s):  
Dynamic Model ◽  
Vibration Isolation ◽  
Force Feedback ◽  
Impedance Control ◽  
Inverse Kinematic ◽  
Control Input ◽  
Control Approach ◽  
Active Vibration ◽  
Robot Body ◽  
Active Vibration Isolation

Abstract Serving Stewart plat as wheel-legged construction, the most outstanding superiority of proposed wheel-legged hybrid robot (WLHR) is active vibration isolation during rolling on rugged terrain. This paper presents a force-driven control approach based on model predictive control (MPC) to design optimal control input for Stewart parallel wheel-leg that locomotes using swing foot trajectory. Adding adaptive impedance control in outermost loop, controlling framework prevents robot body horizontal and from vibration over rolling motion. Through dynamic model of Stewart mechanism, controller first creates predictive model by combining Newton-Euler equation, Newton-Raphson iteration of forward kinematic solving for current configuration, inverse kinematic calculation of Stewart obtaining desired joint position, and Gain/Integration module determining reference torque. With minimizing control deviation and input as objective function, a novel control optimization formulation generates optimum input for each control duration. These actuating force naturally enables each strut stretching and retracting used to realize six degree-of-freedom (6DOF) motion for Stewart wheel-leg. We exploit the variable-adapting method to reasonably adjust environmental impedance parameters by current position, velocity, force feedback of wheel-leg. This allow us to adequately acknowledge the desired support force tracking, isolating robot from isolation that is generated from unknown terrain. We demonstrate the validation of our control methodology on physical prototype by tracking a Bezier curve and active vibration isolation while the robot is rolling on decelerate strip. Respectively given PI controller and a sort of traditional impedance controller as comparison, a better performance of proposed algorithm was operated and evaluated through displacement and force sensors internally-installed in each cylinder, as well as IMU mounted on robot body.

A stance period approach for simplified observation of galloping as applied to canines

Robotica ◽  
2011 ◽  
Vol 30 (4) ◽  
pp. 627-633
Author(s):  
Surya P. N. Singh ◽  
Kenneth J. Waldron
Keyword(s):  
Parameter Estimation ◽  
Conceptual Framework ◽  
Motion Capture ◽  
Contact Force ◽  
Inverse Dynamics ◽  
Force Plate ◽  
Setup Times ◽  
Legged Robot ◽  
Impulse Model ◽  
Leg Motion

SUMMARYThe gallop is the preferred gait by mammals for agile traversal through terrain. This motion is intrinsically complex as the feet are used individually and asymmetrically. Simple models provide a conceptual framework for understanding this gait. In this light, this paper considers the footfall projections as suggested by an impulse model for galloping as a measurement simplifying strategy. Instead of concentrating on forces and inverse dynamics, this view focuses observations on leg motion (footfalls and stance periods) for subsequent gallop analysis and parameter estimation. In practice, this eases experiments (particularly for IR-based motion capture) by extending the experimental workspace, removing the need for single-leg contact force-plate measurements, and reducing the marker set. This provides shorter setup times, and it reduces postprocessing as data are less likely to suffer from occlusion, errant correspondence, and tissue flexion. This approach is tested using with three canine subjects (ranging from 8 to 24 kg) performing primarily rotary gallops down a 15 m runway. Normalized results are in keeping with insights from previous animal and legged robot studies and are consistent with motions suggested by said impulse model.

scholarly journals Dynamic Compliance Analysis for LHDS of Legged Robot, Part A: Position-Based Impedance Control

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 64321-64332 ◽  
Author(s):  
Kai-Xian Ba ◽  
Bin Yu ◽  
Guo-Liang Ma ◽  
Zheng-Jie Gao ◽  
Qi-Xin Zhu ◽  
...  
Keyword(s):  
Impedance Control ◽  
Dynamic Compliance ◽  
Legged Robot

scholarly journals Realization of Force Detection and Feedback Control for Slave Manipulator of Master/Slave Surgical Robot

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7489
Author(s):  
Hu Shi ◽  
Boyang Zhang ◽  
Xuesong Mei ◽  
Qichun Song
Keyword(s):  
Feedback Control ◽  
Force Feedback ◽  
Impedance Control ◽  
Three Dimensional ◽  
Surgical Instruments ◽  
Force Output ◽  
Software Environment ◽  
Force Detection ◽  
Academic Field ◽  
Learning Machine

Robot-assisted minimally invasive surgery (MIS) has received increasing attention, both in the academic field and clinical operation. Master/slave control is the most widely adopted manipulation mode for surgical robots. Thus, sensing the force of the surgical instruments located at the end of the slave manipulator through the main manipulator is critical to the operation. This study mainly addressed the force detection of the surgical instrument and force feedback control of the serial surgical robotic arm. A measurement device was developed to record the tool end force from the slave manipulator. An elastic element with an orthogonal beam structure was designed to sense the strain induced by force interactions. The relationship between the acting force and the output voltage was obtained through experiment, and the three-dimensional force output was decomposed using an extreme learning machine algorithm while considering the nonlinearity. The control of the force from the slave manipulator end was achieved. An impedance control strategy was adopted to restrict the force interaction amplitude. Modeling, simulation, and experimental verification were completed on the serial robotic manipulator platform along with virtual control in the MATLAB/Simulink software environment. The experimental results show that the measured force from the slave manipulator can provide feedback for impedance control with a delay of 0.15 s.

Modeling and Impedance Control of a Two-Manipulator System Handling a Flexible Beam

1997 ◽  
Vol 119 (4) ◽  
pp. 736-742 ◽  
Author(s):  
Dong Sun ◽  
Yunhui Liu
Keyword(s):  
Asymptotic Stability ◽  
Force Feedback ◽  
Impedance Control ◽  
Interaction Force ◽  
Flexible Beam ◽  
New Approach ◽  
Vibration Dynamics ◽  
Lasalle Theorem ◽  
Internal Forces ◽  
Proper Response

This paper presents a new approach of transporting a flexible beam handled by two manipulators to a desired position/orientation while suppressing its vibration, and simultaneously controlling the internal forces between the manipulators and the beam to avoid any damage on the system. The algorithm combines impedance control and an I-type force feedback into one scheme by designing a proper response of the interaction force. No information about the vibration is used in the controller. The asymptotic stability is investigated by using LaSalle theorem, based on the vibration dynamics of the beam approximated by m assumed modes (m → ∞ ). Simulations demonstrate the validity of the proposed method.

scholarly journals Dynamic Compliance Analysis for LHDS of Legged Robot, Part B: Force-Based Impedance Control

IEEE Access ◽  
2018 ◽  
Vol 6 ◽  
pp. 74799-74811 ◽  
Author(s):  
Kaixian Ba ◽  
Bin Yu ◽  
Zhengjie Gao ◽  
Qixin Zhu ◽  
Guoliang Ma ◽  
...  
Keyword(s):  
Impedance Control ◽  
Dynamic Compliance ◽  
Legged Robot

scholarly journals Multi-Robot Trajectory Planning and Position/Force Coordination Control in Complex Welding Tasks

2019 ◽  
Vol 9 (5) ◽  
pp. 924 ◽  
Author(s):  
Yahui Gan ◽  
Jinjun Duan ◽  
Ming Chen ◽  
Xianzhong Dai
Keyword(s):  
Trajectory Planning ◽  
Cooperative Control ◽  
Impedance Control ◽  
Welding Process ◽  
Coordination Control ◽  
Control Approach ◽  
Force Coordination ◽  
Force Tracking ◽  
Robot Systems ◽  
Multi Robot

In this paper, the trajectory planning and position/force coordination control of multi-robot systems during the welding process are discussed. Trajectory planning is the basis of the position/ force cooperative control, an object-oriented hierarchical planning control strategy is adopted firstly, which has the ability to solve the problem of complex coordinate transformation, welding process requirement and constraints, etc. Furthermore, a new symmetrical internal and external adaptive variable impedance control is proposed for position/force tracking of multi-robot cooperative manipulators. Based on this control approach, the multi-robot cooperative manipulator is able to track a dynamic desired force and compensate for the unknown trajectory deviations, which result from external disturbances and calibration errors. In the end, the developed control scheme is experimentally tested on a multi-robot setup which is composed of three ESTUN industrial manipulators by welding a pipe-contact-pipe object. The simulations and experimental results are strongly proved that the proposed approach can finish the welding task smoothly and achieve a good position/force tracking performance.

scholarly journals Powered knee and ankle prosthesis with indirect volitional swing control enables level-ground walking and crossing over obstacles

2020 ◽  
Vol 5 (44) ◽  
pp. eaba6635 ◽  
Author(s):  
Joel Mendez ◽  
Sarah Hood ◽  
Andy Gunnel ◽  
Tommaso Lenzi
Keyword(s):  
Real World ◽  
Gait Pattern ◽  
Crossing Over ◽  
Volitional Control ◽  
Foot Placement ◽  
Control Approach ◽  
Minimum Jerk ◽  
Foot Clearance ◽  
High Level

Powered prostheses aim to mimic the missing biological limb with controllers that are finely tuned to replicate the nominal gait pattern of non-amputee individuals. Unfortunately, this control approach poses a problem with real-world ambulation, which includes tasks such as crossing over obstacles, where the prosthesis trajectory must be modified to provide adequate foot clearance and ensure timely foot placement. Here, we show an indirect volitional control approach that enables prosthesis users to walk at different speeds while smoothly and continuously crossing over obstacles of different sizes without explicit classification of the environment. At the high level, the proposed controller relies on a heuristic algorithm to continuously change the maximum knee flexion angle and the swing duration in harmony with the user’s residual limb. At the low level, minimum-jerk planning is used to continuously adapt the swing trajectory while maximizing smoothness. Experiments with three individuals with above-knee amputation show that the proposed control approach allows for volitional control of foot clearance, which is necessary to negotiate environmental barriers. Our study suggests that a powered prosthesis controller with intrinsic, volitional adaptability may provide prosthesis users with functionality that is not currently available, facilitating real-world ambulation.

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