參數(shù)資料
型號: MC68HC16Z1
廠商: Motorola, Inc.
英文描述: 16-Bit Modular Microcontroller(16位模塊化微控制器)
中文描述: 16位微控制器模塊(16位模塊化微控制器)
文件頁數(shù): 3/20頁
文件大?。?/td> 210K
代理商: MC68HC16Z1
AN1213/D
MOTOROLA
3
TRANSFER FUNCTION TERMS
Each of the transfer function terms affects system performance.
The P Term
The
Proportional
P term amplifies the error signal by a constant amount. However, P is not in series, but in parallel with I and
D, which implies that P cannot be used to scale the transfer function amplitude at all frequencies. Instead,
the P term interacts with the I and D terms to determine the placement of the zeros in the controller open-
loop transfer function.
Figure 2
shows a root locus solution to the numerator of Equation 1 as P is varied
with respect to I and D.
term is the most subtle and perhaps most misunderstood term in the PID algorithm. The
Figure 2 Effect of Varying P on Zeros
The I Term
The
Integral
integrated error mixed to the output of the filter, any I value other than zero implies that
can be tolerated by the servo loop. In other words, given sufficient time, a PID control loop will eventually
servo the output to the exact value of the commanded input.
term gives the servo loop that inflexible, stubborn feel. Since the I term adjusts the amount of
no
steady state error
In the frequency domain, the I term also affects placement of the zeros, as shown in
one of the zeros is at s = –P/D, and the other zero is at s = 0, which means that it will cancel the integrator
pole at s = 0. This makes sense intuitively since the integrator is turned off if I equals zero. As I increases,
the servo loop becomes “snappier”, i.e., it responds more quickly to steady state error.
Figure 3
. For I = 0,
It appears that adding an integrator to the servo loop would be a panacea for motion control headaches.
However, while adding an integrator does address steady state error, it can also have a negative impact on
system dynamics. The effect is most easily seen in the time domain. Consider a linear PID system that per-
forms servo control. Initially, the controlled motor is at rest, with zero position error. Torque is applied to the
motor shaft, changing its position and holding it in the new position. The control system senses a steady-
state error and tries to return the shaft to the commanded position. Since the example system is linear, con-
trol voltage continues to increase as a result of integrated error. While the increasing control voltage could
cause the motor to overheat, this is not the only detrimental effect. If the applied torque is suddenly removed
while integrator output is large, the motor shaft will spin past the desired shaft position while control voltage
is “dumped”. Eventually, a zero steady-state condition is achieved, but in an underdamped (and potentially
unacceptable) manner. Because this situation is similar to winding up a spring and then letting it go, the term
“wind-up” is used to describe it. Techniques to mitigate wind-up are discussed later in this note.
DELTA P ON AN1213
P = 0
P =
P = 0
(I
÷
D)
P =
P =
(4DI)
– j
(I
÷
D)
j
(I
÷
D)
S PLANE
相關(guān)PDF資料
PDF描述
MC68HC24 Port Replacement Unit (PRU)
MC68HC24D Port Replacement Unit (PRU)
MC68HC705J Microcontrollers
MC68HC705K1 8-Bit Microcontroller Units (MCU).(8位微控制器)
MC68HC705KJ1 8-Bit Microcontroller Units (MCU).(8位微控制器)
相關(guān)代理商/技術(shù)參數(shù)
參數(shù)描述
MC68HC16Z1CAG 制造商:Freescale Semiconductor 功能描述:
MC68HC16Z1CAG16 功能描述:16位微控制器 - MCU 16 BIT MCU 1K RAM RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時(shí)鐘頻率:24 MHz 程序存儲(chǔ)器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風(fēng)格:SMD/SMT
MC68HC16Z1CAG16 制造商:Freescale Semiconductor 功能描述:IC16-BIT MICROCONTROLLER
MC68HC16Z1CAG20 功能描述:16位微控制器 - MCU 16 BIT MCU 1K RAM RoHS:否 制造商:Texas Instruments 核心:RISC 處理器系列:MSP430FR572x 數(shù)據(jù)總線寬度:16 bit 最大時(shí)鐘頻率:24 MHz 程序存儲(chǔ)器大小:8 KB 數(shù)據(jù) RAM 大小:1 KB 片上 ADC:Yes 工作電源電壓:2 V to 3.6 V 工作溫度范圍:- 40 C to + 85 C 封裝 / 箱體:VQFN-40 安裝風(fēng)格:SMD/SMT
MC68HC16Z1CAG20 制造商:Freescale Semiconductor 功能描述:Microcontroller