逢 甲 大學
自動控制工程學系碩士班
碩 士 論 文
以 SimMechanics 建模備有簡易力量模
型與仿生式控制器之移動機器人
The Use of SimMechanics for Modeling The
Mobile Robot with A Simple Force Model and A
Biologically-Inspired Controller
指導教授:林南州
學 生:廖哲偉
中 華民國一百零三年六月
以SimMechanics 建模備有簡易力量模型與仿生式控制器之移動機器人
Abstract
This thesis mainly describes the dynamical model for a hexapod robot which is a
product of Parallax. The model is built by using Simulink with add-on SimMechanics
which provides a multibody environment for 3D mechanical systems. A simple force
model is employed for the purpose of simulating the reaction between legs and
ground and a biologically-inspired controller is also incorporated in order to make the
robot imitate walking characteristics of insects. Through the simulation of the model,
it provides informations of displacements, velocities, posture angles as well as ground
reactions. Two common insects gait patterns, high-speed tripod gait and low-speed
metachronal gait, are chosen. The simulation results are used to validate the model
and, then, proceed to analyze the characteristics for each gait pattern.
Keywords: SimMechanics, hexapod, reaction
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逢甲大學e-Theses & Dissertations (102 學年度)
以SimMechanics 建模備有簡易力量模型與仿生式控制器之移動機器人
每一隻腳另有垂直旋轉一個自由度,圖2.6為說明垂直旋轉自由度,其中腳
的實體圖如圖2.7 所示,AB、BC、CD 和DE、EF、FG 桿件為兩個四連桿機構,
HI 桿件作為腳和地面接觸的部分,透過伺服機驅動AB 桿件,因其連桿原理,
進而使HI 桿件做向上向下運動,來達到六足機器人每隻腳做抬起、放下的動作。
圖2.6 六足機器人垂直旋轉示意圖
圖2.7 腳的實體圖
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逢甲大學e-Theses & Dissertations (102 學年度)
C
A B
D
E
F
G
H
I
以SimMechanics 建模備有簡易力量模型與仿生式控制器之移動機器人
Entry
地面下腳在地面上
地面上或地面下?
Return
腳有接觸地面;
利用簡易力量模型計算腳與地面之間
的反作用力
圖3.4 狀態判斷
腳沒有接觸地面;
腳與地面之間反作用力為0
若是腳和地面有形成接觸,則把腳對地面的運動視為是一種球體對地面運動
的情況,將球體當成一個點,而點對地面的相對運動形成一個點對點的接觸運動,
此項運動為一項三維的空間運動,我們把地模擬為一個具有彈簧、阻尼的系統,
其X、Y、Z 方向皆具有彈簧、阻尼,如圖3.5 所示,圖中P 為腳和地面接觸的
接觸點,PFoot 為當前腳的位置,透過與地面接觸點的位置、穿透深度和當時腳的
速度VFoot,以及地面給予的彈性和阻尼性能作用在接觸點的關係來得到其反作
用力,如式(3.1),其中KGround 為地面的彈性係數,CGround 為地面的阻尼係數,其
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PFoot
逢甲大學e-Theses & Dissertations (102 學年度)
流程如圖3.6。
P
圖3.5 X、Y、Z 方向的彈簧阻尼系統
X
Z Y
Leg
PFoot
24.
以SimMechanics 建模備有簡易力量模型與仿生式控制器之移動機器人
()
( )
( )
× ×
- -
- -
- -
F K P P C V
FootX Ground X FootX Ground FootX
= = × ×
F F K P P C V
Foot FootY Ground Y FootY Ground FootY
× ×
F K P P C V
FootZ Ground Z FootZ Ground FootZ
Entry
利用彈簧、阻尼來計算腳
與地面之間的反作用力
Return
圖3.6 計算反作用力
而腳和地面接觸的過程中,還要考慮是否有打滑的情況發生,所以不光是計
算反作用力,還需計算水平力及最大靜摩擦力,接著判斷水平力是否有大於最大
靜摩擦力,以此判斷來作為是否有發生打滑的依據,水平力FFootHorMag 的算法如
式(3.2),最大靜摩擦力SFriction 算法如式(3.3),其中s m
正向力。如果水平力大於最大靜摩擦力,表示腳與地面之間有滑動現象,此時X、
Y 方向反作用力不等於式(3.1),而是動摩擦力;另外,也必須計算滑動後新的接
F = F 2+F 2 (3.2)
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(3.1)
為靜摩擦係數,FFootZ 為
逢甲大學e-Theses & Dissertations (102 學年度)
觸點P,其流程如圖3.7。
FootHorMag FootX FootY
= × s FootZ SFriction m F (3.3)
25.
以SimMechanics 建模備有簡易力量模型與仿生式控制器之移動機器人
計算水平力、最大靜摩擦力
Yes No
水平力>最大靜摩擦力
發生打滑; 沒有發生打滑
修正X、Y方向的反作用力及接觸點P
圖3.7 判斷腳是否打滑
若腳發生打滑則需要修正X、Y 方向的反作用力和接觸點P,而這時我們的
X、Y 方向的反作用力FFootX 及FFootY 要依據我們的動摩擦力來做更改,而動摩擦
F = cos KFriction
F = sin KFriction
q
q
P = P + cos SFriction / K
P = P + sin SFriction / K
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逢甲大學e-Theses & Dissertations (102 學年度)
力KFriction 算法如式(3.4),其中k m
為動摩擦係數,修正FFootX 及FFootY 的算法如
式(3.5),其中q 為水平力FFootHorMag 和X 軸的夾角,並且接觸點P 則需要依靠靜
摩擦力來做更改,因為我們使用的模型具有阻尼的特性,所以接觸點P 不能以動
摩擦力作為更改的依據,而是仍要透過靜摩擦力來更改我們的接觸點P[22],如
式(3.6)所示,其流程如圖3.8。
KFriction =mk ×FFootZ (3.4)
×
×
FootX
FootY
q
q
(3.5)
×
×
X FootX Ground
Y FootY Ground
(3.6)
Entry
Return
以SimMechanics 建模備有簡易力量模型與仿生式控制器之移動機器人
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