2001 Fiscal Year Final Research Report Summary
MOTION CONTROL TAKING ENERGY RECYCLING INTO ACCOUNT
| Project/Area Number |
12650292
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | Keio University |
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Principal Investigator |
OHNISHI Kouhei Keio University, Faculty of Science and Technology, Professor, 理工学部, 教授 (80137984)
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| Project Period (FY) |
2000 – 2001
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| Keywords | Recycling / Motion Control / Connection / Reachable Matrix / Energy Flow / Interactive Kinematics / Inverter / Power Converter |
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| Research Abstract |
The industry is spending almost half of the total energy used in Japan. It is necessary and important to save energy in production and assembling. In spite of COP3 agreement in Kyoto protocol, C02 emission in Japan is exceeding the agreed value in the year of 2010. The seven items have been determined to accomplish above requirement. Some of them are related to the efficient management of energy. However industry tends to introduce the automation devices to reduce the number of workers in the production lines. Such automation devices will save workers, however, they need more energy. In general the supplied energy in production is consumed in the motion control, and finally it turns to heat. The total efficiency of energy is not so high. This causes the lower efficient usage of energy and as a result the energy consumption in automated factory is going up and up. To overcome this problem, this project is proposing the efficient usage of energy in motion control.
The research of this pro
… More
ject was done in the following schedule.
1. Proposal of the efficient control of energy in motion systems
2. Analysis of energy exchange
3. Design methodology of controller
4. Implementation of the proposed system
5. Future prospect
The idea of this project is based on recycling of regenerative power in motion systems. A robot with plural degrees-of-freedom is actuated by the same numbers of electric motors. Their energy is supplied with inverters, however all of them do not convert the electric power to mechanical power. Some of them are operated in regenerative mode. In production line, there are a lot of robots which are making their motion synchronously. Since one motor is connected to one inverter, there are many inverters which are operated in regenerative mode. However, in most of the cases, the regenerative power is consumed in the resistor installed in inverter. This generates the necessary braking, however deteriorates the efficiency of motion systems. If the regenerative power is used in other joint, which will improve the total efficiency. The principle is not limited to drive of joint of robot. It is needless to say that this principle is applicable to general motion systems if interactive kinematics is sufficiently taken into account.
The energy transfer from the inverters in regenerative mode to the inverters in motoring mode is automatically done if they are connected to the same DC link line. This means they should have common DC link. To realize the smooth transfer of energy, it is necessary to control not only timing of switching from regenerative mode to motoring mode, but also balancing the power flow. This control should be carried out in hard real-time manner based on the connection matrix which is derived from the mechanical power flow. The reachable matrix is easily calculated from connection matrix which shows the overall energy flow. This research intends to show the feasibility of the system in robotic systems. In 2000 and 2001 academic year, the effort was concentrated to the design of controller for FTP based motion control.
The numerical arid preliminary experiments has shown that the improvement of the efficiency of the energy consumption is attained by controlling the alignment of starting time to starting and braking. The algorithm is applied to walking machine, since it has plural degrees-of-freedom. RT-Linux is employed as a real-time operating system of controller. To minimize the delay of communications, the RT-messenger developed in another research group is used. Thanks to such a hard real-time system, the controller of timing of each motion system can be synchronized.
In conclusions, this research project has shown the viability of hard real-time system to realize recycling of energy in motion systems. The energy transfer from regenerated power supply to motoring power supply is smoothly realized. Less
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Research Products
(4 results)
