|
气动软停止配置及原理 |
||||||||||||||||||||
|
下面以SPC10气动软停止配置及原理为例介绍。传统解决气动停止的方案：见图1a传统解决方案，以1无杆气缸DGP/DGPL为例，两边配置两个单向节流阀3，一个双电控电磁阀4，及至少配置一个液压缓冲器，液压缓冲器是制动停止的关键部件。液压缓冲器能强制使活塞速度降为零，但它还需要吸收冲击动能转化为热能，需要有这一过程，需要时间，运动节拍受到限制，同时高速运行的活塞在终端位置时还带来冲击振动和冲击颤抖，给整个机架或机械装置带来破坏 SPC软停止技术：见图1b的SPC软停止技术，它的配置与气动伺服定位技术相似，气动驱动软制动系统由气动直线驱动器2、位移传感器1、三位五通比例方向控制阀4及终端位置控制器6组成。这是一个闭环的控制系统，位移传感器跟踪气动驱动器的位置变化，连续不断地将电压信号反馈到终端位置控制器内，通过运算后不断调整对比例阀的设定值，然后将此设定值输入到气动流量伺服阀，气动流量伺服阀根据设定值不断调整阀芯位置，从而对输出流量进行重新配置。终端位置控制器在调试系统开始时，按2s以上的一个自校按钮，就可对系统进行自校(按动自校开关后让气缸自始至终完成一次行走)，将气缸的直径、实际行程长度、负载、摩擦力等参数通过自校过程采集，并对这些参数进行处理。与气动伺服定位技术不同的是它采用终端位置控制器6(见图2)，是气动伺服技术中简化版优化配置计算软件控制器，它根据气缸的直径、行程、负载制作了六个位置的DIL拨动开关，详见下表。需要补充的是气缸额定的行程应减去其两端的非有效行程(FESTO称为行程保留值，安装调试用的挡块安装距离)。三位五通比例方向控制阀(又称气动流量伺服阀)的详细功能，参见电-气动比例/伺服系统及产品中相关叙述。气动软停止的终端位置控制器与电-气动比例/伺服系统中的控制器一样，在调试开始时已记录下从零至终端位置，并把它转换为0~10V或4~20mA(电信号数值)，一旦转换成“输出＝设定位置－当前位置＋5V”。当终端位置满足此公式，三位五通气动流量伺服阀处于中封位置，活塞被止动。如图3所示，气动驱动软制动系统(soft stop)的速度最高点不在终点，而是在约2/3行程处，然后速度开始下降，直到终点时，速度刚刚等于零，这一功能也是终端位置控制器预设的，要达到精确止动，详见气动软停止的仿真运动曲线分析，并需参照下表的规定值选取缸径、行程及负载等参数(该表为摘录说明，仅反映当缸径为25mm，行程360~500mm，质量2~30kg时部分列表
图1
图2
图3 |
||||||||||||||||||||
|
缸径-行程 |
25-360 |
缸径-行程 |
25-450 |
缸径-行程 |
25-500 |
|||||||||||||||
|
负载质量 /kg |
拨动开关 |
负载质量 /kg |
拨动开关 |
负载质量 /kg |
拨动开关 |
|||||||||||||||
|
1 |
2 |
3 |
4 |
5 |
6 |
1 |
2 |
3 |
4 |
5 |
6 |
1 |
2 |
3 |
4 |
5 |
6 |
|||
|
2 |
ON |
ON |
ON |
OFF |
OFF |
OFF |
2 |
OFF |
ON |
OFF |
OFF |
OFF |
OFF |
2 |
OFF |
ON |
ON |
OFF |
OFF |
OFF |
|
4 |
ON |
ON |
OFF |
ON |
OFF |
OFF |
4 |
OFF |
ON |
OFF |
ON |
OFF |
OFF |
4 |
OFF |
ON |
OFF |
ON |
OFF |
OFF |
|
6 |
ON |
ON |
ON |
ON |
OFF |
OFF |
6 |
OFF |
ON |
ON |
ON |
OFF |
OFF |
6 |
OFF |
ON |
ON |
ON |
OFF |
OFF |
|
8 |
ON |
ON |
ON |
ON |
OFF |
OFF |
8 |
OFF |
ON |
ON |
ON |
OFF |
OFF |
8 |
OFF |
ON |
OFF |
OFF |
ON |
OFF |
|
10 |
OFF |
ON |
ON |
ON |
OFF |
OFF |
10 |
OFF |
ON |
OFF |
OFF |
ON |
OFF |
10 |
ON |
OFF |
OFF |
OFF |
ON |
OFF |
|
12 |
OFF |
ON |
OFF |
OFF |
ON |
OFF |
12 |
OFF |
ON |
ON |
OFF |
ON |
OFF |
12 |
ON |
OFF |
OFF |
OFF |
ON |
OFF |
|
14 |
OFF |
ON |
OFF |
OFF |
ON |
OFF |
14 |
OFF |
ON |
ON |
OFF |
ON |
OFF |
14 |
ON |
OFF |
ON |
OFF |
ON |
OFF |
|
16 |
OFF |
ON |
ON |
OFF |
ON |
OFF |
16 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
16 |
ON |
OFF |
ON |
OFF |
ON |
OFF |
|
18 |
OFF |
ON |
ON |
OFF |
ON |
OFF |
18 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
18 |
ON |
OFF |
OFF |
ON |
ON |
OFF |
|
20 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
20 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
20 |
ON |
OFF |
OFF |
ON |
ON |
OFF |
|
22 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
22 |
OFF |
ON |
ON |
ON |
ON |
OFF |
22 |
ON |
OFF |
OFF |
ON |
ON |
OFF |
|
24 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
24 |
OFF |
ON |
ON |
ON |
ON |
OFF |
24 |
ON |
OFF |
ON |
ON |
ON |
OFF |
|
26 |
OFF |
ON |
OFF |
ON |
ON |
OFF |
26 |
OFF |
ON |
ON |
ON |
ON |
OFF |
26 |
ON |
OFF |
ON |
ON |
ON |
OFF |
|
28 |
ON |
ON |
ON |
ON |
ON |
OFF |
28 |
OFF |
ON |
ON |
ON |
ON |
OFF |
28 |
OFF |
ON |
OFF |
OFF |
OFF |
ON |
|
30 |
ON |
ON |
ON |
ON |
ON |
OFF |
30 |
OFF |
ON |
OFF |
OFF |
OFF |
ON |
30 |
OFF |
ON |
OFF |
OFF |
OFF |
ON |
