具力量增益的機械手臂之創新與設計

Abstract

在裝設如電線杆等大型柱狀體時往往需要出動大型吊車，但有時會因為場地限制而無法前往且費用昂貴，於是希望設計能安裝於工程車上並能抓取重物柱狀體的機械手臂來取代作業，但重量限制一直為關鍵的因素，所以將利用重力補償來提高所能抓取的重量。 綠色環保意識高漲，節能減碳已成為大家的課題。於是本研究運用重力平衡理論，應用於三臂式機械手臂中第一臂和第二臂來抵銷本身的重力位能，第三臂及抓取物的重力位能則利用滑軌及渦卷彈簧能提供等張力的概念來完成部分的重力補償，達成在動靜態中減輕動力源扭矩進而降低所需的能量。 重力平衡和等張力的重力補償用模擬軟體來進行不同裝設重力補償機構狀況下對於減輕機械手臂的負載效益探討，並探討移動速度對於扭矩及功率的影響，最後將其放大為實體大小探討實行的可能性，最後利用模型實驗來驗證模擬軟體的可靠度，並提出一個新型並聯式彈簧吊車的概念。 實驗數據與模擬的比較，驗證模擬軟體具有一定的可靠度，放大至實體大小的電線杆抓取上發現其扭矩以市面上伺服馬達加入減速機構確實可達到，代表具有可行性。

關鍵字：重力平衡、等張力、機械手臂

It usually uses a large crane to install utility poles and other large cylindrical body. But sometimes large cranes cannot drive to destination due to road conditions and the asking price is not cheap. So, we want to design a mechanical arm which can be installed on a machine shop truck with middle size and can crawl heavy cylindrical body to replace a large crane. Because the weight limit has been a key factor, we would like to use the gravity balance theory in order to lift the larger weight. In this paper, the scheme for improving loading uses in the gravity balance theory. In this three arms manipulator, the first and second arm’s weight will use gravity balance theory to offset its gravitational potential energy. The third arm and crawling things of the gravitational potential energy using slide and scroll spring to provide constant force to do part of gravity compensation. This design reduces torque of the power source in the static and dynamic operation and reduces the energy requirement. In simulation software, we set different conditions of the compensation mechanism to confer their saving efficiency. Then, the effect of different working speeds on torque and power are compared. Experimental data verify that have some the reliability on simulation. The real model of the NCCI2011 robot (NCTU CIDM Column Installation Robot) enlarged proportionally from the laboratory scale is also reconstructed and evaluated by using Dynamic simulation system (e.g. COSMOS Motion). The feasible driving motors and the dynamic performance of the proposed robot are also evaluated and investigated with some demonstrate examples.

Key Words: Gravity Balance, Constant Tension, Robot Arm