scholarly journals High-Bandwidth Active Impedance Control of the Proprioceptive Actuator Design in Dynamic Compliant Robotics

Actuators ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 71 ◽  
Author(s):  
Simon Hjorth Jessing Lund ◽  
Peter Billeschou ◽  
Leon Bonde Larsen
Keyword(s):  
Pulse Width Modulation ◽  
Compliant Mechanisms ◽  
Controller Design ◽  
Impedance Control ◽  
Experimental Tests ◽  
Angle Sensor ◽  
High Performing ◽  
High Bandwidth ◽  
Torque Observer ◽  
Active Impedance

Dynamic compliant robotics is a fast growing field because of its ability to widen the scope of robotics. The reason for this is that compliant mechanisms may ensure safe/compliant interactions between a robot and an external element—for instance, a human operator. Active impedance control may widen the scope even further in relation to passive elements, but it requires high-bandwidth robust torque and active impedance control which induces high-noise issues even if high-end sensors are used. To address these issues, a complete controller design scheme, including Field-Oriented Control (FOC) of a Brushless Direct Current (BLDC) motor, is proposed. In this paper, controller designs for controlling the virtual impedance, motor torque and field are proposed which enables high-bandwidth robust control. Additionally, a novel speed and angle observer is proposed that aims to reduce noise arising in the angle sensor (typically a 12-bit magnetic encoder) and a Kalman/Luenberger based torque observer is proposed that aims to reduce noise arising in the phase current sensors. Through experimental tests, the combination of the controller designs and observers facilitated a closed-loop torque bandwidth of 2 . 6 k Hz and a noise reduction of 13 . 5 (in relation to no observers), at a sample rate and Pulse Width Modulation (PWM) frequency of 25 k Hz . Additionally, experiments verified a precise and high performing controller scheme both during impacts and at a variety of different virtual compliance characteristics.

scholarly journals AC Current Ripple in Three-Phase Four-Leg PWM Converters with Neutral Line Inductor

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1430
Author(s):  
Aleksandr Viatkin ◽  
Riccardo Mandrioli ◽  
Manel Hammami ◽  
Mattia Ricco ◽  
Gabriele Grandi
Keyword(s):  
Numerical Simulations ◽  
Pulse Width Modulation ◽  
Neutral Line ◽  
Experimental Tests ◽  
Performance Comparison ◽  
Design Parameters ◽  
Switching Frequency ◽  
Three Phase ◽  
Ac Current ◽  
Current Ripple

This paper presents a comprehensive study of peak-to-peak and root-mean-square (RMS) values of AC current ripples with balanced and unbalanced fundamental currents in a generic case of three-phase four-leg converters with uncoupled AC interface inductors present in all three phases and in neutral. The AC current ripple characteristics were determined for both phase and neutral currents, considering the sinusoidal pulse-width modulation (SPWM) method. The derived expressions are simple, effective, and ready for accurate AC current ripple calculations in three- or four-leg converters. This is particularly handy in the converter design process, since there is no need for heavy numerical simulations to determine an optimal set of design parameters, such as switching frequency and line inductances, based on the grid code or load restrictions in terms of AC current ripple. Particular attention has been paid to the performance comparison between the conventional three-phase three-leg converter and its four-leg counterpart, with distinct line inductance values in the neutral wire. In addition to that, a design example was performed to demonstrate the power of the derived equations. Numerical simulations and extensive experimental tests were thoroughly verified the analytical developments.

Adaptive Control of Pulse Width Modulation Voltage-Source Rectifier with Disturbance Signals

2013 ◽  
Vol 385-386 ◽  
pp. 977-980
Author(s):  
Bao Bin Liu
Keyword(s):  
Pulse Width ◽  
Pulse Width Modulation ◽  
Controller Design ◽  
Adaptive Controller ◽  
Voltage Source ◽  
Robust Controller ◽  
Reference Velocity ◽  
Velocity Tracking ◽  
Modulation Voltage ◽  
Robust Controller Design

A nonlinear adaptive controller is proposed for the design of pulse width modulation voltage-source rectifier with disturbance signals of harmonics to achieve reference velocity tracking. The procedure of the robust controller design is developed via improved backstepping method. With the proposed controller, PWM voltage-source rectifiers can guarantee accuracy of output voltage tracking. Global asymptotic stability of the closed-loop system has been proved. The simulation results demonstrate effectiveness of the presented method.

Piezoelectric Actuator Performance Metrics and Relation to Compliant Mechanism Design

2001 ◽  
Author(s):  
Hima Maddisetty ◽  
Mary Frecker
Keyword(s):  
Topology Optimization ◽  
Performance Metrics ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Mechanical Efficiency ◽  
High Energy ◽  
High Energy Density ◽  
High Bandwidth ◽  
Compliant Mechanism Design ◽  
Actuator Performance

Abstract Piezoceramic actuators have gained widespread use due to their desirable qualities of high force, high bandwidth, and high energy density. Compliant mechanisms can be designed for maximum stroke amplification of piezoceramic actuators using topology optimization. In this paper, the mechanical efficiency and other performance metrics of such compliant mechanism/actuator systems are studied. Various definitions of efficiency and other performance metrics of actuators with amplification mechanisms from the literature are reviewed. These metrics are then applied to two compliant mechanism example problems and the effect of the stiffness of the external load is investigated.

scholarly journals Towards versatile legged robots through active impedance control

2015 ◽  
Vol 34 (7) ◽  
pp. 1003-1020 ◽  
Author(s):  
Claudio Semini ◽  
Victor Barasuol ◽  
Thiago Boaventura ◽  
Marco Frigerio ◽  
Michele Focchi ◽  
...  
Keyword(s):  
Impedance Control ◽  
Legged Robots ◽  
Active Impedance

Modeling, identification, and controller design for hydraulic anti-slip braking system

2018 ◽  
Vol 233 (4) ◽  
pp. 862-876 ◽  
Author(s):  
Bijan Moaveni ◽  
Pegah Barkhordari
Keyword(s):  
Control System ◽  
Controller Design ◽  
Longitudinal Velocity ◽  
Experimental Tests ◽  
Identification Algorithm ◽  
Slip Ratio ◽  
Control Approach ◽  
The Road ◽  
Braking System ◽  
Road Condition

This study modeled and identified the hydraulic subsystem of an anti-slip braking system using input–output data of experiments on a test car. A simulation was prepared based on the results of the identification process, and it was validated by comparing the simulation results with those of the experimental tests. A novel control approach is introduced to obtain the optimal slip ratio during braking. This method does not require vehicle longitudinal velocity for the control algorithm but requires information about the road condition (dry, wet, etc.). An online identification algorithm to detect the road condition is introduced. The main benefits of the proposed control system in comparison with previous versions are improving the braking performance, simplicity of the control strategy, and considering the operational constraints which facilitate the control system implementation. The simulation and hardware-in-the-loop experimental results demonstrated the success of the modeling, identification, and proposed control approach.

scholarly journals Cascaded Control of Flexible-Joint Robots Based on Sliding-Mode Estimator Approach

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Genliang Xiong ◽  
Jingxin Shi ◽  
Haichu Chen
Keyword(s):  
Controller Design ◽  
Sliding Mode ◽  
Joint Stiffness ◽  
Perturbation Approach ◽  
Regular Form ◽  
Flexible Joint ◽  
Flexible Joint Robots ◽  
Highly Nonlinear ◽  
Position Controller ◽  
High Bandwidth

The inherent highly nonlinear coupling and system uncertainties make the controller design for a flexible-joint robot extremely difficult. The goal of the control of any robotic system is to achieve high bandwidth, high accuracy of trajectory tracking, and high robustness, whereby the high bandwidth for flexible-joint robot is the most challenging issue. This paper is dedicated to design such a link position controller with high bandwidth based on sliding-mode technique. Then, two control approaches ((1) extended-regular-form approach and (2) the cascaded control structure based on the sliding-mode estimator approach) are presented for the link position tracking control of flexible-joint robot, considering the dynamics of AC-motors in robot joints, and compared with the singular perturbation approach. These two-link position controllers are tested and verified by the simulation studies with different reference trajectories and under different joint stiffness.

A Simple Analog Feed-Forward Controller Design for DC-DC Buck Converter

2015 ◽  
Vol 643 ◽  
pp. 61-67
Author(s):  
Shu Wu ◽  
Yasunori Kobori ◽  
Haruo Kobayashi
Keyword(s):  
Transient Response ◽  
Pulse Width Modulation ◽  
Controller Design ◽  
Buck Converter ◽  
Charge Balance ◽  
Feed Forward ◽  
Feed Forward Control ◽  
Single Output ◽  
Output Capacitor ◽  
Feed Forward Controller

This paper presents usage of analog feed-forward control to improve the transient response of DC-DC buck converters with pulse-width-modulation (PWM). The analog feed-forward controller is simple and does not require complicated calculations. Duty cycle is modulated directly based on the charge balance of the output capacitor. Compared with conventional feedback control, this simple feed-forward controller reduces control delay and provides a satisfactory transient response. We apply this technique to a Single-Inductor-Dual-Output (SIDO) buck converter as well as a Single-Inductor-Single-Output (SISO) buck converter, and show that its cross-regulation is improved. We have validated the proposed method with SIMetrix simulations.

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