Actuation System and Control Concept for a Running Biped

2007 ◽  
pp. 219-231 ◽  
Author(s):  
T. Luksch ◽  
K. Berns ◽  
F. Flörchinger
Keyword(s):  
Actuation System ◽  
Control Concept ◽  
And Control

scholarly journals A Dedicated Design Strategy for Active Boring Bar

2019 ◽  
Vol 9 (17) ◽  
pp. 3541 ◽  
Author(s):  
Niccolò Grossi ◽  
Lisa Croppi ◽  
Antonio Scippa ◽  
Gianni Campatelli
Keyword(s):  
Operating Conditions ◽  
Dynamic Characterization ◽  
Control Logic ◽  
Boring Bar ◽  
Actuation System ◽  
Static Equivalence ◽  
And Control ◽  
Cutting System ◽  
Damping Systems ◽  
Critical Aspects

Unstable vibrations (i.e., chatter) onset is one of the main limits to productivity in deep boring bar processes. Active damping systems allow to increase machining stability in different configurations (i.e., tool setup), without requiring cutting system dynamic characterization. Design of an active boring bar involves the development of monitoring system (sensors), actuation system and control logic. While several control logics were evaluated and discussed, few design solutions were presented in the literature, focusing only on building prototypes to demonstrate control logic effectiveness. In the presented work, a deep analysis of the main issues and requirements related to active boring design was carried out and a systematic approach to tackle all the critical aspects was developed. The results of the proposed method are: (i) optimal actuators positioning able to damp vibration along two directions; (ii) preload system design guaranteeing the correct actuator preloading for the operating conditions; (iii) covers design to protect actuators and ensure the dynamic and static equivalence between active and standard boring bar. Following this approach, an active boring bar was designed, realized and tested. The results prove the required equivalence between active and original boring bar and assess the damping effect.

Design and Control of a Compact and Flexible Pneumatic Artificial Muscle Actuation System: Part Two—Robust Control

2011 ◽  
Author(s):  
Sai-Kit Wu ◽  
Garrett Waycaster ◽  
Tad Driver ◽  
Xiangrong Shen
Keyword(s):  
Robust Control ◽  
Nonlinear Model ◽  
Sliding Mode ◽  
Artificial Muscle ◽  
Control Approach ◽  
Actuation System ◽  
Highly Nonlinear ◽  
Pressure Dynamics ◽  
System Part ◽  
And Control

A robust control approach is presented in this part of the paper, which provides an effective servo control for the novel PAM actuation system presented in Part I. Control of PAM actuation systems is generally considered as a challenging topic, due primarily to the highly nonlinear nature of such system. With the introduction of new design features (variable-radius pulley and spring-return mechanism), the new PAM actuation system involves additional nonlinearities (e.g. the nonlinear relationship between the joint angle and the actuator length), which further increasing the control difficulty. To address this issue, a nonlinear model based approach is developed. The foundation of this approach is a dynamic model of the new actuation system, which covers the major nonlinear processes in the system, including the load dynamics, force generation from internal pressure, pressure dynamics, and mass flow regulation with servo valve. Based on this nonlinear model, a sliding mode control approach is developed, which provides a robust control of the joint motion in the presence of model uncertainties and disturbances. This control was implemented on an experimental setup, and the effectiveness of the controller demonstrated by sinusoidal tracking at different frequencies.

Supervisory Control of Drilling

1996 ◽  
Vol 118 (1) ◽  
pp. 10-19 ◽  
Author(s):  
R. J. Furness ◽  
A. Galip Ulsoy ◽  
C. L. Wu
Keyword(s):  
Process Control ◽  
Torque Control ◽  
Feed Speed ◽  
Machining Time ◽  
Control Approach ◽  
Drilling Operation ◽  
Control Functions ◽  
Control Concept ◽  
Supervisory Process ◽  
And Control

A supervisory process control approach to machining is presented in this paper, and demonstrated by application to a drilling operation. The supervisory process control concept incorporates optimization and control functions in a hierarchical structure. This approach utilizes feedback measurements to parameterize the constraints of a process optimization problem whose solution determines both strategies and references for process control. For this particular drilling operation, a three-phase strategy (utilizing a combination of feed, speed, and torque control) evolved due to inherent variation in constraint activity as a function of hole depth. A controller comparison study was conducted which demonstrates the advantages of this approach compared to (1) uncontrolled “conventional” drilling, (2) feed and speed controlled drilling, and (3) torque and speed controlled drilling. Benefits of reduced machining time, improved hole quality, and the elimination of tool breakage are demonstrated, and the potential economic impact is highlighted for an example production application.

Design of a Compliant Industrial Gripper Driven by a Bistable Shape Memory Alloy Actuator

2020 ◽  
Author(s):  
Dominik Scholtes ◽  
Stefan Seelecke ◽  
Gianluca Rizzello ◽  
Paul Motzki
Keyword(s):  
Shape Memory ◽  
High Energy ◽  
Industrial Applications ◽  
High Energy Density ◽  
Small Scale ◽  
Monitoring And Control ◽  
Actuation System ◽  
First Results ◽  
Functional Prototype ◽  
And Control

Abstract Within industrial manufacturing most processing steps are accompanied by transporting and positioning of workpieces. The active interfaces between handling system and workpiece are industrial grippers, which often are driven by pneumatics, especially in small scale areas. On the way to higher energy efficiency and digital factories, companies are looking for new actuation technologies with more sensor integration and better efficiencies. Commonly used actuators like solenoids and electric engines are in many cases too heavy and large for direct integration into the gripping system. Due to their high energy density shape memory alloys (SMA) are suited to overcome those drawbacks of conventional actuators. Additionally, they feature self-sensing abilities that lead to sensor-less monitoring and control of the actuation system. Another drawback of conventional grippers is their design, which is based on moving parts with linear guides and bearings. These parts are prone to wear, especially in abrasive environments. This can be overcome by a compliant gripper design that is based on flexure hinges and thus dispenses with joints, bearings and guides. In the presented work, the development process of a functional prototype for a compliant gripper driven by a bistable SMA actuation unit for industrial applications is outlined. The focus lies on the development of the SMA actuator, while the first design approach for the compliant gripper mechanism with solid state joints is proposed. The result is a working gripper-prototype which is mainly made of 3D-printed parts. First results of validation experiments are discussed.

scholarly journals A new active asymmetry monitoring and control technique applied to critical aircraft flap control system failures

2019 ◽  
Vol 304 ◽  
pp. 04011
Author(s):  
Dario Belmonte ◽  
Matteo Davide Lorenzo Dalla Vedova ◽  
Gaetano Quattrocchi
Keyword(s):  
Control System ◽  
Flight Control ◽  
Angular Position ◽  
Control Technique ◽  
Monitoring And Control ◽  
Active Monitoring ◽  
Actuation System ◽  
Left And Right ◽  
And Control ◽  
Current Monitoring

Asymmetry limitation requirements between left and right wing flap surfaces play an important role in the design of the implementation of the secondary flight control system of modern airplanes. In fact, especially in the case of sudden breaking of one of the torsion bars of the flap transmission line, the huge asymmetries that can rapidly develop could compromise the lateral-directional controllability of the whole aircraft (up to cause catastrophic occurrences). Therefore, in order to guarantee the aircraft safety (especially during take-off and landing flight phase in which the effects of asymmetries could generate uncontrollable aircraft attitudes), it is mandatory to timely detect and neutralize these asymmetries. The current monitoring techniques generally evaluate the differential angular position between left and right surfaces and, in most the events, limit the Flaps Control System (FCS) asymmetries, but in severe fault conditions (e.g. under very high aerodynamic loads), unacceptable asymmetries could be generated, compromising the controllability of the aircraft. To this purpose, in this paper the authors propose a new active monitoring and control technique capable of detecting the increasing angular error between the different flap surfaces and that, after stopping the whole actuation system, acts on the portion of the actuation line still connected to the PDU to minimize the FCS asymmetries.

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