Drive technology for peristaltic and rotary pumps

Abstract

A method and system for controlling a rotary pump where a rotary pump can be coupled to a stepper motor, and the stepper motor can be controlled with micro- or nano-stepping accuracy using a processor controlled drive system. The processor controlled drive system moves the stepper motor according to a predetermined move profile; this causes the rotary pump to dispense a precision amount of fluid. The rotary pump can be a peristaltic pump or any other type of pump. The rotary pump can be coupled to the stepper motor through a reduction gear with a reduction ratio of 2:1 or similar. The stepper motor can be mechanically coupled to a rotational position encoder so that a measure of the rotation position can be fed back to the processor. The processor can cause the stepper motor to interpolate between pulse positions of the encoder.

1 . A method of controlling a rotary pump comprising the steps of: 
 coupling a rotary pump to a stepper motor, wherein said stepper motor is controlled with micro- or nano-stepping accuracy using a processor controlled drive system;    causing said processor controlled drive system to move said stepper motor according to a predetermined move profile, wherein said rotary pump dispenses a precision amount of fluid.    
   
   
       2 . The method of  claim 1  wherein said rotary pump is a peristaltic pump.  
   
   
       3 . The method of  claim 1  further comprising the step of causing said rotary pump to be coupled to said stepper motor through a reduction gear.  
   
   
       4 . The method of  claim 3  wherein said reduction gear is 2:1 or greater.  
   
   
       5 . The method of  claim 1  further comprising sensing a rotational position of said stepper motor using a rotary encoder.  
   
   
       6 . The method of  claim 5  wherein said processor interpolates between positions of said rotary encoder.  
   
   
       7 . The method of  claim 1  wherein said stepper motor has a resolution of at greater than 70,000 steps per revolution.  
   
   
       8 . The method of  claim 1  further comprising causing said stepper motor to operate at a plurality of different resolutions during a dispense cycle.  
   
   
       9 . The method of  claim 8  wherein said stepper motor operates at both 1000 steps per revolution and at least 10,000 steps per revolution during a dispense cycle.  
   
   
       10 . An apparatus for dispensing fluid comprising: 
 a rotary pump;    a stepper motor coupled to said rotary pump;    a nano-stepping drive system under control of a processor driving said stepper motor;    a move profile stored in said processor for causing said stepper motor to move said rotary pump a predetermined amount to dispense a predetermined amount of fluid.    
   
   
       11 . The apparatus of  claim 10  wherein said rotary pump is a peristaltic pump.  
   
   
       12 . The apparatus of  claim 10  further comprising a rotary encoder coupled to said stepper motor.  
   
   
       13 . The apparatus of  claim 12  wherein said processor causes said stepper motor to interpolate between positions of said rotary encoder.  
   
   
       14 . The apparatus of  claim 10  further comprising a reduction gear between said rotary pump and said stepper motor.  
   
   
       15 . The apparatus of  claim 14  wherein said reduction gear is 2:1 or greater.  
   
   
       16 . A method for precision fluid dispensing comprising the steps of: 
 causing a processor to control a stepping position of at least one stepper motor;    coupling a stepper motor driver for driving a stepper motor to said processor and to said stepper motor;    coupling a peristaltic pump mechanically to said stepper motor, said processor causing said peristaltic pump to rotate with a stepping precision of at least 10,000 steps per revolution.    
   
   
       17 . The method of  claim 16  wherein said stepping precision is greater than 125,000 steps per revolution.  
   
   
       18 . The method of  claim 16  further comprising placing a reduction gear between said stepper motor and said peristaltic pump.  
   
   
       19 . The method of  claim 16  further comprising coupling an optical encoder mechanically to said stepper motor, said optical encoder electrically also coupled to said processor.  
   
   
       20 . The method of  claim 19  wherein said processor causes said stepper motor to interpolate between positions of said optical encoder.