scholarly journals Modeling and Experimental Design for the On-Orbit Inertial Parameter Identification of Free-Flying Space Robots

2005 ◽  
Author(s):  
Roberto Lampariello ◽  
Gerhard Hirzinger
Keyword(s):  
Energy Consumption ◽  
Experimental Design ◽  
Parameter Identification ◽  
Suitable Model ◽  
Space Robots ◽  
Full System ◽  
End Effector ◽  
Dynamic Motion ◽  
Inertial Parameters ◽  
Flying Robot

A method is proposed for the identification of the inertial parameters of a free-flying robot directly in orbit, using accelerometers. This can serve to improve the path planning and tracking capabilities of the robot, as well as its efficiency in energy consumption. The method is applied to the identification of the base body and of the load on the end-effector, giving emphasis to the experimental design. The problem of the identification of the full system is also addressed in its theoretical aspects. The experience from the Getex Dynamic Motion experiments performed on the ETS-VII satellite have allowed to determine a most suitable model for the identification.

Model Discrimination and Parameter Identification by an Experimental Design Strategy

1998 ◽  
Vol 31 (8) ◽  
pp. 73-78 ◽  
Author(s):  
R. Takors ◽  
D. Weuster-Botz ◽  
W. Wiechert ◽  
C. Wandrey
Keyword(s):  
Experimental Design ◽  
Parameter Identification ◽  
Design Strategy ◽  
Model Discrimination

scholarly journals Model Calibration for a Rigid Hexapod-Based End-Effector with Integrated Force Sensors

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3537
Author(s):  
Christian Friedrich ◽  
Steffen Ihlenfeldt
Keyword(s):  
Parameter Identification ◽  
Degrees Of Freedom ◽  
Force Measurement ◽  
Experimental Studies ◽  
Measurement Model ◽  
Calibration Procedure ◽  
Force Sensors ◽  
End Effector ◽  
Measurement Models ◽  
Fast Procedure

Integrated single-axis force sensors allow an accurate and cost-efficient force measurement in 6 degrees of freedom for hexapod structures and kinematics. Depending on the sensor placement, the measurement is affected by internal forces that need to be compensated for by a measurement model. Since the parameters of the model can change during machine usage, a fast and easy calibration procedure is requested. This work studies parameter identification procedures for force measurement models on the example of a rigid hexapod-based end-effector. First, measurement and identification models are presented and parameter sensitivities are analysed. Next, two excitation strategies are applied and discussed: identification from quasi-static poses and identification from accelerated continuous trajectories. Both poses and trajectories are optimized by different criteria and evaluated in comparison. Finally, the procedures are validated by experimental studies with reference payloads. In conclusion, both strategies allow accurate parameter identification within a fast procedure in an operational machine state.

scholarly journals Kinematically redundant actuators, a solution for conflicting torque–speed requirements

2019 ◽  
Vol 38 (5) ◽  
pp. 612-629 ◽  
Author(s):  
Tom Verstraten ◽  
Raphael Furnémont ◽  
Pablo López-García ◽  
David Rodriguez-Cianca ◽  
Bram Vanderborght ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Degree Of Freedom ◽  
Potential Solution ◽  
Maximum Acceleration ◽  
Average Efficiency ◽  
Single Motor ◽  
Operating Range ◽  
Dynamic Motion ◽  
Redundant Actuators ◽  
Working Point

Robots often switch from highly dynamic motion to delivering high torques at low speeds. The actuation requirements for these two regimes are very different. As a consequence, the average efficiency of the actuators is typically much lower than the efficiency at the optimal working point. A potential solution is to use multiple motors for a single motor joint. This results in a redundant degree of freedom, which can be exploited to make the system more efficient overall. In this work, we explore the potential of kinematically redundant actuators in dynamic applications. The potential of a kinematically redundant actuator with two motors is evaluated against a single-motor equivalent in terms of operating range, maximum acceleration, and energy consumption. We discuss how the comparison is influenced by the design of the actuator and the way how the power is distributed over the input motors. Our results support the idea that kinematically redundant actuators can resolve the conflicting torque–speed requirements typical of robots.

Parameter Identification for Model-Based Control of Hydraulically Actuated Open-Chain Manipulators

2019 ◽  
Author(s):  
Lionel Hulttinen ◽  
Janne Koivumäki ◽  
Jouni Mattila
Keyword(s):  
Parameter Identification ◽  
Nonlinear Model ◽  
A Priori ◽  
Chamber Pressure ◽  
Hydraulic Actuator ◽  
Open Chain ◽  
Model Based Control ◽  
Model Based ◽  
Inertial Parameters ◽  
Manipulator Link

Abstract In this paper, a nonlinear model-based controller with parameter identification is designed for a rigid open-chain manipulator arm actuated by servovalve-controlled hydraulic cylinders. The arising problem in adopting model-based controllers is how to acquire accurate estimates of system parameters, with limited available information about either the hydraulic actuator parameters or manipulator link inertial parameters. The objective of this study is to identify both the rigid-body parameters of the links and the hydraulic actuator parameters from collected cylinder chamber pressure and joint angle data, while no a priori knowledge of these parameters is available. Same physical plant models are used for control design as well as for parameter identification. Experimental results show that the proposed nonlinear model-based control scheme results in acceptable Cartesian position tracking performance in free-space motion when using the identified parameters.

Inverse kinematics of free-floating space robots with minimum dynamic disturbance

Robotica ◽  
1996 ◽  
Vol 14 (6) ◽  
pp. 667-675 ◽  
Author(s):  
Fengfeng Xi
Keyword(s):  
Inverse Kinematics ◽  
New Method ◽  
Space Robots ◽  
Simple Fact ◽  
Generalized Jacobian ◽  
Space Manipulator ◽  
End Effector ◽  
Dynamic Disturbance ◽  
Space Manipulators

In this paper a new method is presented for solving the inverse kinematics of free-floating space manipulators. The idea behind the method is to move the space manipulator along a path with minimum dynamic disturbance. The method is proposed to use the manipulator Jacobian instead of the generalized Jacobian of the spacecraft-manipulator system. This is based on the simple fact that, if the space manipulator moves along the so-called Zero Disturbance Path (ZDP), the spacecraft is immovable. As a result, the space manipulator can in this case be treated as a terrestrial fixed-based manipulator. Hence, the motion mapping between the joints and the end-effector can be described directly by the manipulator Jacobian. In the case that the ZDP does not exist, it can be shown that the solutions obtained by the proposed method provide a path with minimum dynamic disturbance.

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