|
|
【20160404】Follower Motion Schemes
! u1 O0 z2 {- m* W+ v9 ?3 a: r從動(dòng)件運(yùn)動(dòng)模式+ B+ q7 f2 P+ _, i5 N7 w
% K+ o+ P8 M& jIn designing a cam, the objective is to identify a suitable shape for the cam. The primary interest is to ensure that the follower will achieve the desired displacements. The shape of the cam is merely a means to obtain this motion." P9 o3 x! r! W* l
設(shè)計(jì)凸輪時(shí)，我們的目標(biāo)是找出合適的凸輪外形。但最初的目的是確保從動(dòng)件將按照預(yù)期進(jìn)行運(yùn)動(dòng)。凸輪外形僅僅是獲得此種運(yùn)動(dòng)的方式。
3 q) U. y9 }9 ]3 O/ p
; u7 D/ U. u# A+ G r9 x1 {5 dConstant Velocity：Uniform velocity, and zero acceleration) I$ |2 X7 Z/ [9 a
常速運(yùn)動(dòng)：勻速，加速度為零
; e7 R0 _& d' I- e; |Problems：The instantaneous jump from one constant value of velocity to another constant value of velocity results in an infinite acceleration.
) m, ?& y1 f) N1 [: C m6 l問(wèn)題：從一種勻速狀態(tài)到另一狀態(tài)，所需加速度無(wú)限大。% c1 F# S- I+ q9 n7 o+ J
未命名圖片.png (48.84 KB, 下載次數(shù): 89)
下載附件
保存到相冊(cè)
constant velocity
2016-4-4 17:55 上傳
* \$ H* r/ z$ H( G$ e/ |Constant Acceleration：Constant positive and negative accelerations2 u5 r9 x9 l( a$ s; X! Y+ Q1 b% n
勻加速運(yùn)動(dòng)：加速度連續(xù)同向
9 i7 X" Q/ L* k) C/ h" nProblems：The abrupt changes of acceleration at the end of the motion result in abrupt changes in inertial forces.
' Y5 f2 N" P/ @* [問(wèn)題：加速度突然轉(zhuǎn)變，所需內(nèi)力無(wú)限大。8 w ?( R9 `+ c1 ?. M6 h$ `
未命名圖片.png (58.12 KB, 下載次數(shù): 87)
下載附件
保存到相冊(cè)
constant acceleration
2016-4-4 17:57 上傳
9 ^& A9 }6 W1 O7 ^+ p+ Y8 W ?" G
Harmonic Motion：Harmonic motion is derived from trigonometric functions, thus exhibiting very smooth motion curves.' J7 u g/ r& T0 z0 C
簡(jiǎn)諧運(yùn)動(dòng)：三角函數(shù)推導(dǎo)而來(lái)，因此具有平滑的運(yùn)動(dòng)曲線。
0 k7 r0 i; H o& H9 K; S& Q& |Problems：It has a sudden change of acceleration at the ends of the motion, which can be objectionable at higher speeds.) O7 ]0 h" h3 v8 a N8 W5 D
問(wèn)題：在運(yùn)動(dòng)末尾加速度會(huì)突變，這在高速下十分不便。
, X% c5 K* I' {, u( g, h7 E
未命名圖片.png (62.31 KB, 下載次數(shù): 96)
下載附件
保存到相冊(cè)
harmonic motion
2016-4-4 18:02 上傳
, r* c; S+ o7 n, b2 T3 c X1 _* vCycloidal Motion：Cycloidal motion is another motion scheme derived from trigonometric functions.
# ~8 J, y3 g( L+ a; r: W* T+ d擺線運(yùn)動(dòng)：另一種由三角函數(shù)導(dǎo)出的運(yùn)動(dòng)類(lèi)型。" K/ b, N+ u' A1 h% U: \, |4 v8 I
This scheme does not have the sudden change in acceleration at the ends of the motion, which makes it popular for high-speed applications.3 }! i) w" f( Y* J3 s; Q
加速度不突變，在高速運(yùn)動(dòng)中廣為應(yīng)用。
/ m9 A( Y5 N$ ^" d
未命名圖片.png (63.86 KB, 下載次數(shù): 84)
下載附件
保存到相冊(cè)
cycloidal motion
2016-4-4 18:04 上傳
, r/ u u: I8 G+ i) @& R0 h
6 S5 |0 m1 ]4 |; q& e, p# fThe time derivative of the acceleration is referred to as jerk.3 ^9 L. F) y) q
加速度對(duì)時(shí)間的導(dǎo)數(shù)稱(chēng)為急動(dòng)度。
/ V2 h0 P( m b, @) Q9 y9 E" C5 p4 Z! s4 o% M- \' H- L @
A summary of the peak velocity, peak acceleration, and peak jerk for the different motion schemes, as a function of the rise H and period of the interval T, is shown in Table 9.5.
) w9 C1 Y& s7 Z9 p; P- Q; m: O, l3 Q如表所示是各種運(yùn)動(dòng)模式的速度峰值、加速度峰值及急動(dòng)度峰值的對(duì)比。" X3 C- G8 \* J, k
Cha 07-2016.jpg (79.4 KB, 下載次數(shù): 85)
下載附件
保存到相冊(cè)
Table 9.5
2016-4-4 18:08 上傳
- Z# ?6 S# ^% w2 \) e% b, x' d; T! J: [* I
|
|
樓主: 黑森林的鹿
發(fā)表于 2016-4-2 19:44:06
) j) M' U' M! K2 v7 k
、表示上個(gè)學(xué)期也是力學(xué)拖了大后腿，6級(jí)也就是勉強(qiáng)過(guò)了，想想自己刷分目標(biāo)僅是過(guò)500，再看看樓主，實(shí)在是慚愧。這個(gè)學(xué)期在搞機(jī)械創(chuàng)新，感覺(jué)知識(shí)實(shí)在是不夠用，不過(guò)也因此更加有興趣去學(xué)專(zhuān)業(yè)課，嗯，向樓主學(xué)習(xí)，據(jù)說(shuō)，不帶手機(jī)上課就成功了一半呢
) m' i! }6 J1 q