远动学 CA=fi 平面运动方程{y=/() 对于每一瞬时t,都可以求出对应的xA,y42,图形S 在该瞬时的位置也就确定了。 二.平面运动分解为平动和转动 当图形S上A点不动时,则刚体作定轴转动 当图形S上g角不变时,则刚体作平动 故刚体平面运动可以看成是平动和转动的合成运动 16
16 二．平面运动分解为平动和转动 当图形Ｓ上Ａ点不动时，则刚体作定轴转动 当图形Ｓ上 角不变时，则刚体作平动． 故刚体平面运动可以看成是平动和转动的合成运动． xA , yA , 平面运动方程 ( ) 1 x f t A = ( ) 2 y f t A = ( ) 3 = f t 对于每一瞬时 t ，都可以求出对应的 ， 图形S 在该瞬时的位置也就确定了
Kinematics Example Motion of a wheel The plane motion of the wheel can be viewed as the composition of the translation with the vehicle body and the O rotation relative to the vehicle Plane motion of the wheel relative to the static reference system (absolute motion) Translation of the vehicle body (moving system Ax'y) relative to static system (convected motion) Rotation of the wheel relative to the vehicle(moving system Ary) (relative motion)
17 Example Motion of a wheel． The plane motion of the wheel can be viewed as the composition of the translation with the vehicle body and the rotation relative to the vehicle. Plane motion of the wheel relative to the static reference system (absolute motion) Translation of the vehicle body (moving system Ax y ) relative to static system (convected motion) Rotation of the wheel relative to the vehicle (moving system Ax y) (relative motion)
例如车轮的运动 车轮的平面运动可以看成 是车轮随同车厢的平动和相对 车厢的转动的合成 O 车轮对于静系的平面运动(绝对运动) 车厢(动系Axy)相对静系的平动(牵连运动) 车轮相对车厢(动系Axy)的转动(相对运动) 18
18 例如 车轮的运动． 车轮的平面运动可以看成 是车轮随同车厢的平动和相对 车厢的转动的合成． 车轮对于静系的平面运动 （绝对运动） 车厢（动系Ax y ) 相对静系的平动 （牵连运动） 车轮相对车厢（动系Ax y）的转动 （相对运动）
Kinematics The arbitrarily selected point a is called a pole. Thus A plane motion of a rigid body can be decomposed A into a translation with a pole △y and a rotation about the po Plane motion of a wheel A A Translation with the pole A Rotation about the pole A
19 The arbitrarily selected point A is called a pole. Thus, Plane motion of a wheel Translation with the pole A Rotation about the pole A A plane motion of a rigid body can be decomposed into a translation with a pole and a rotation about the pole．
远动学 我们称动系上的原点A为基点,于是刚体的平面运动可以 分解为随基点的平动 A )=上和绕基点的转动 车轮的平面运动 A ( 随基点4的平动 绕基点A的转动 20
20 我们称动系上的原点Ａ为基点，于是 车轮的平面运动 随基点A的平动 绕基点A'的转动 刚体的平面运动可以 分解为随基点的平动 和绕基点的转动．