Development of Sensor-Less Power-Assisted System with Disturbance Observer Considering High Friction

2013 ◽  
Vol 25 (6) ◽  
pp. 1020-1028
Author(s):  
Takanori Miyoshi ◽  
◽  
Ryosuke Imai ◽  
Kazuhiko Terashima ◽  
Kanemitsu Ochiai ◽  
...  
Keyword(s):  
High Power ◽  
Disturbance Observer ◽  
High Speed ◽  
Static Friction ◽  
Force Sensor ◽  
Direct Drive ◽  
Speed Reduction ◽  
Drive Motor ◽  
Support Device ◽  
Friction Parameters

Japan has a dwindling birthrate and a rapidly aging population, which has led to an increasing number of elderly laborers. Although this has spurred development into power-assisted (PA) equipment that can reduce the physical demands, most of power assisted systems developed so far have used the force sensor, a direct drive motor, or a high power motor. The PA machine using force sensor is unable to detect and avoid obstacles that might collide with nonsensor components of the machine. The direct drive motor is too expensive for the practical use and its power tends to increase. According to Japanese law, a high power motor is not allowed to cooperate together with laborers in the factory. Thus, in this research, a sensor-less power-assisted (PA) system capable of estimating operator force based on a disturbance observer and friction correction is designed and built for a high friction production support device using a lowcapacity servo motor and a high-speed reduction ratio reducer. First, a dynamic model of a production support device is identified with specific friction parameters. Next, a sensor-less PA system is constructed that is equipped with an appropriate disturbance observer and dynamic friction correction. Moreover, the static friction issues are solved by the regular driving command. Finally, the accuracies of estimated force are examined, and the effectiveness of the constructed sensor-less PA system is verified.

Design and Control of Planar Parallel Mechanisms with High Speed and High Precision

2006 ◽  
Vol 315-316 ◽  
pp. 872-0
Author(s):  
L.N. Sun ◽  
Y.J. Liu ◽  
J. Li ◽  
J. Cui
Keyword(s):  
High Precision ◽  
Disturbance Observer ◽  
High Speed ◽  
Optimization Design ◽  
Advanced Manufacturing ◽  
Parallel Mechanisms ◽  
Direct Drive ◽  
End Effector ◽  
Load Disturbance ◽  
And Control

In order to satisfy the requirement of advanced manufacturing equipments with high speed and high precision, two planar parallel mechanisms have been developed. Based on these mechanisms, firstly, in consideration with the velocity and the precision of the end-effector together, the dimension optimization design is performed based on conditioning index and the precision characteristics. Then a disturbance observer is designed for the purpose of restraining load disturbance in the direct-drive system, and the experimental results show that load disturbance can be effectively restrained by the disturbance observer.

Motion Control of Ultra-High-Speed Manipulator with a Flexible Link Based on Dynamically Coupled Driving

2006 ◽  
Vol 18 (5) ◽  
pp. 598-607 ◽  
Author(s):  
Tomoari Maruyama ◽  
◽  
Chunquan Xu ◽  
Aiguo Ming ◽  
Makoto Shimojo
Keyword(s):  
Motion Control ◽  
High Speed ◽  
Wrist Joint ◽  
High Accuracy ◽  
Human Motion ◽  
Golf Club ◽  
Direct Drive ◽  
Flexible Link ◽  
Ultra High Speed ◽  
Drive Motor

We have developed a golf robot whose swing simulates human motion. The design concept is to realize ultra-high-speed dynamic manipulation using a dexterous mechanism. The robot consists of a shoulder joint with a high-power direct-drive motor and a wrist joint with a low-power direct-drive motor. High-speed golf swings are realized by a sort of motion control, called dynamically-coupled driving which compensates for the lack of drive in the wrist joint. In this paper a new model accounting for golf club flexibility with all parameters identified in experiments was developed. Based on this, we generated and implemented trajectories for different criteria. Experimental results confirmed the high accuracy of motion control and the feasibility of golf club flexibility in ultra-high-speed manipulation.

Disturbance Observers for Rigid Mechanical Systems: Equivalence, Stability, and Design

2002 ◽  
Vol 124 (4) ◽  
pp. 539-548 ◽  
Author(s):  
Erwin Schrijver ◽  
Johannes van Dijk
Keyword(s):  
Disturbance Rejection ◽  
Disturbance Observer ◽  
High Speed ◽  
Design Procedure ◽  
Systematic Design ◽  
Direct Drive ◽  
Robot Tracking ◽  
Feedback Structure ◽  
Drive Systems ◽  
The One

Mechanical (direct-drive) systems designed for high-speed and high-accuracy applications require control systems that eliminate the influence of disturbances like cogging forces and friction. One way to achieve additional disturbance rejection is to extend the usual (P(I)D) controller with a disturbance observer. There are two distinct ways to design, represent, and implement a disturbance observer, but in this paper it is shown that the one is a generalization of the other. A general systematic design procedure for disturbance observers that incorporates stability requirements is given. Furthermore, it is shown that a disturbance observer can be transformed into a classical feedback structure, enabling numerous well-known tools to be used for the design and analysis of disturbance observers. Using this feedback interpretation of disturbance observers, it will be shown that a disturbance observer based robot tracking controller can be constructed that is equivalent to a passivity based controller. By this equivalence not only stability proofs of the disturbance observer based controller are obtained, but it also provides more transparent controller parameter selection rules for the passivity based controller.

scholarly journals AdjustSense: Adaptive 3D Sensing System with Adjustable Spatio-Temporal Resolution and Measurement Range Using High-Speed Omnidirectional Camera and Direct Drive Motor

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 6975
Author(s):  
Mikihiro Ikura ◽  
Sarthak Pathak ◽  
Jun Younes Louhi Kasahara ◽  
Atsushi Yamashita ◽  
Hajime Asama
Keyword(s):  
Temporal Resolution ◽  
High Speed ◽  
Measurement Range ◽  
Direct Drive ◽  
Multiple Measurement ◽  
Sensing System ◽  
Drive Motor ◽  
3D Sensing ◽  
Spatio Temporal ◽  
Conventional Systems

Many types of 3D sensing devices are commercially available and were utilized in various technical fields. In most conventional systems with a 3D sensing device, the spatio-temporal resolution and the measurement range are constant during operation. Consequently, it is necessary to select an appropriate sensing system according to the measurement task. Moreover, such conventional systems have difficulties dealing with several measurement targets simultaneously due to the aforementioned constants. This issue can hardly be solved by integrating several individual sensing systems into one. Here, we propose a single 3D sensing system that adaptively adjusts the spatio-temporal resolution and the measurement range to switch between multiple measurement tasks. We named the proposed adaptive 3D sensing system “AdjustSense.” In AdjustSense, as a means for the adaptive adjustment of the spatio-temporal resolution and measurement range, we aimed to achieve low-latency visual feedback for the adjustment by integrating not only a high-speed camera, which is a high-speed sensor, but also a direct drive motor, which is a high-speed actuator. This low-latency visual feedback can enable a large range of 3D sensing tasks simultaneously. We demonstrated the behavior of AdjustSense when the positions of the measured targets in the surroundings were changed. Furthermore, we quantitatively evaluated the spatio-temporal resolution and measurement range from the 3D points obtained. Through two experiments, we showed that AdjustSense could realize multiple measurement tasks: 360∘ 3D sensing, 3D sensing at a high spatial resolution around multiple targets, and local 3D sensing at a high spatio-temporal resolution around a single object.

Spring-Assisted Motorized Transmission for Efficient Hover by Four Flapping Wings

2018 ◽  
Vol 10 (6) ◽  
Author(s):  
Yao-Wei Chin ◽  
Ziyuan Ang ◽  
Yukai Luo ◽  
Woei-Leong Chan ◽  
Javaan S. Chahl ◽  
...  
Keyword(s):  
High Speed ◽  
Beat Frequency ◽  
Electrical Power ◽  
Micro Air Vehicles ◽  
Flapping Wings ◽  
Direct Drive ◽  
Flexible Wings ◽  
Speed Reduction ◽  
Brushless Motor ◽  
Lower Disk

Elastic storage has been reported to help flying insects save inertial power when flapping their wings. This motivates recent research and development of elastic storage for flapping-wing micro air vehicles (fwMAVs) and their ground (tethered) flight tests. The previous designs of spring-loaded transmissions are relatively heavy or bulky; they have not yet been adopted by freely hovering prototypes of fwMAVs, especially those with four flapping wings. It is not clear if partial elastic storage can still help save power for flapping flight while not overloading the motorized transmission. Here, we developed ultralight and compact film hinges as elastic storage for four flapping wings. This spring-assisted transmission was motor driven such that the wing beat frequency was higher than the natural frequency of elastically hinged wings. Our experiments show that spring recoil helps accelerate wing closing thus generating more thrust. When powered by a 3.18 g brushless motor, this 13.4 g fwMAV prototype with spring-assisted transmission can take off by beating four flexible wings (of 240 mm span) with up to 21–22 g thrust generation at 22–23 Hz. Due to lower disk loading and high-speed reduction, indirect drive of the four elastically hinged wings can produce a thrust per unit of electrical power of up to 4.6 g/W. This electrical-power-specific thrust is comparable to that generated by direct drive of a propeller, which was recommended by the motor (AP-03 7000kv) manufacturer.

scholarly journals An Improvement Proposal to the Static Friction Model

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Sergio Sánchez-Mazuca ◽  
Ricardo Campa
Keyword(s):  
Large Scale ◽  
Static Friction ◽  
Control Area ◽  
Friction Model ◽  
Rate Of Change ◽  
Direct Drive ◽  
Mechatronic Systems ◽  
Proposed Model ◽  
Drive Motor ◽  
Friction Models

Friction is a force acting against the relative motion between two surfaces in contact. This phenomenon is present in all mechanical systems and has a great impact on the control area. The design of mechatronic systems and the compensation techniques require a broad knowledge of the effects that friction produces. The phenomenon has two well-defined phases: static friction presents before the motion between the surfaces in contact is clearly visible, while kinetic friction appears when that motion at large scale has already started. There are different friction models for each of those phases. In this work we propose an improvement to the static friction models, which consist in assuming that the maximum static friction coefficient is no more a constant but a function of the rate of change of the external force that produces the motion. After explaining and justifying the proposal, the procedure for obtaining the parameters of the new model is mentioned. At the end, an experimental study on a direct-drive motor allows us to validate the proposed model.

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