This paper is concerned with summarizing the categories of impedance control showing the feature and the limitations of each category. Much attention is paid to variable impedance control considering the possible control schemes, performance, the stability, the integration of constant/variable compliant elements with the host robots, etc.
For a long time, the robotics community concentrated on improving the performance of the robotic systems in free space. The advanced control strategies for position control could not be sufficient to stabilize the motion of robots in constrained spaces. In general, there are two categories of force control schemes with miscellaneous subdivisions: hybrid position-force control and impedance control. The former is well suitable for well-known interaction environment, however, it does not consider the dynamic interaction between robot end-effector and the environment. In contrast, impedance control includes regulation and stabilization of robot motion via creating a mathematical relationship between the interaction forces and the reference trajectories.
In general, a mass-spring-damper impedance filter is used for stabilization purposes. Tuning the parameters of the impedance filter is not trivial and may lead to unstable contact if an unsuitable strategy is used. The human, however, has amazing control systems with advanced biological actuators. He/she can manipulate the muscles stiffness to softly comply to the interaction forces. Accordingly, the parameters of the impedance filter should be time-varying rather than value-constant in order to meet the human behavior during interaction tasks.
Inhaltsverzeichnis (Table of Contents)
- 1. Introduction
- 2. Background
- 2.1 Dynamic modeling of robots in constrained motion
- 3. Force Tracking Position-Based Impedance Control
- 4. Variable Impedance Control
- 5. Impedance Control of Flexible Joints with Constant and Variable Compliance
- 6. Conclusion
Zielsetzung und Themenschwerpunkte (Objectives and Key Themes)
This paper aims to summarize different impedance control schemes, highlighting their features, limitations, and stability issues. It focuses particularly on variable impedance control, exploring control schemes, performance, and stability, and examines the integration of constant/variable compliant elements with robots.
- Categorization and comparison of impedance control schemes
- Detailed analysis of variable impedance control
- Investigation of multi-loop control for constant and variable impedance actuators
- Stability analysis and performance evaluation of impedance control systems
- Integration of active impedance control with passive compliant elements
Zusammenfassung der Kapitel (Chapter Summaries)
1. Introduction: This introductory chapter sets the stage by explaining the limitations of traditional position control strategies in constrained robotic environments. It highlights the need for force control, contrasting hybrid position-force control with impedance control, emphasizing the latter's ability to dynamically relate interaction forces and reference trajectories using a mass-spring-damper model. The chapter introduces the concept of variable impedance control, mimicking human adaptability, and the challenges in tuning impedance parameters for stable contact. The limitations of conventional impedance control are also touched upon, laying the groundwork for the exploration of advanced techniques in subsequent sections.
2. Background: This chapter provides foundational knowledge on impedance control. It introduces the concept of impedance control as a dynamic relationship between interaction force/torque and robot end-effector trajectory, utilizing a virtual mass-spring-damper system. The chapter details the typical two-nested control loops (outer impedance and inner position/force control) and discusses the dynamic modeling of robots experiencing interaction forces, emphasizing the importance of task coordinate frames and the description of the end-effector's dynamic behavior for high-performance control. It briefly touches upon sub-categories of impedance control (stiffness, compliance, and damping control).
Schlüsselwörter (Keywords)
Impedance control, Force control, Admittance control, Variable impedance control, Series elastic actuators, Variable impedance actuators, Human-robot interaction, Compliant mechanisms, Stability analysis, Control schemes.
FAQ: A Comprehensive Language Preview of Impedance Control Schemes
What is the main topic of this paper?
This paper provides a comprehensive overview of impedance control schemes used in robotics, focusing on variable impedance control and its applications. It analyzes different control strategies, their stability, performance, and integration with compliant elements.
What are the key themes explored in this paper?
The paper explores the categorization and comparison of various impedance control schemes, delves into the specifics of variable impedance control, investigates multi-loop control for impedance actuators, analyzes the stability and performance of these systems, and examines the integration of active impedance control with passive compliant elements.
What are the objectives of this paper?
The paper aims to summarize different impedance control schemes, highlighting their features, limitations, and stability issues. It particularly focuses on variable impedance control, exploring control schemes, performance, and stability, and examines the integration of constant/variable compliant elements with robots.
What are the chapter summaries?
Chapter 1 (Introduction): Introduces the limitations of traditional position control in constrained environments, highlighting the need for impedance control. It introduces variable impedance control and its challenges.
Chapter 2 (Background): Provides foundational knowledge on impedance control, detailing the two-nested control loops and dynamic modeling of robots experiencing interaction forces. It also briefly discusses sub-categories of impedance control.
The remaining chapters (3, 4, and 5) detailed in the Table of Contents focus on specific implementations and analysis of Force Tracking Position-Based Impedance Control, Variable Impedance Control, and Impedance Control of Flexible Joints.
Chapter 6 (Conclusion): This chapter is not summarized in the provided text.
What are the key words associated with this paper?
Impedance control, Force control, Admittance control, Variable impedance control, Series elastic actuators, Variable impedance actuators, Human-robot interaction, Compliant mechanisms, Stability analysis, Control schemes.
What types of impedance control are discussed?
The paper discusses various impedance control schemes, with a particular emphasis on variable impedance control. It also touches upon stiffness, compliance, and damping control as sub-categories.
What are the limitations of conventional impedance control addressed in the paper?
The paper highlights the limitations of traditional position control and conventional impedance control in constrained robotic environments, paving the way for the exploration of more advanced techniques like variable impedance control.
What is the significance of variable impedance control?
Variable impedance control is highlighted for its ability to mimic human adaptability in dynamic environments, overcoming limitations of fixed impedance parameters. The paper explores its control schemes, performance, and stability extensively.
What is the role of compliant elements in the context of this paper?
The paper investigates the integration of both constant and variable compliant elements (like series elastic actuators) with robots to enhance the performance and robustness of impedance control systems.
What type of control loops are discussed?
The paper discusses two-nested control loops: an outer impedance loop and an inner position/force control loop. The interaction and coordination between these loops are crucial for effective impedance control.
- Quote paper
- Dr. Hayder Al-Shuka (Author), Kareem Jawad Kadhim (Author), 2020, An Introduction to Impedance Control of Constrained Robotic Mechanisms, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/958860
