Surveying instrument and a method for drive control thereof
AssigneesNikon Geotecs Co., Ltd., Nikon Corporation
InventorNaoaki Hamada
Life of this patent
Estimating the term…
Abstract
A surveying instrument assumes either a high-speed drive control mode for driving a surveying optical system at high speed or a low-speed drive control mode for driving the surveying optical system at low speed. A motor is continuously driven through a PWM control method in the high-speed drive control mode. Then, the low-speed drive control mode is selected to drive the motor so as to allow the motor to alternate acceleration and a virtual stop. As the surveying optical system approaches a predetermined position, a condition for next motor acceleration is set based upon the detected rotational angle of the surveying optical system. Thus, it becomes possible to stop the surveying optical system at the predetermined position with a high degree of accuracy.
Claims14
A surveying instrument comprising:
- a surveying optical system to be oriented toward a surveying target;
- a drive motor that drives said surveying optical system;
- a first drive control circuit that outputs a first drive signal having a first frequency and a first pulse duty cycle and used to continuously drive said drive motor;
- a second drive control circuit that outputs a second drive signal having a second frequency and a second pulse duty cycle and used to drive said drive motor so as to allow said drive motor to alternate accelerations and a virtual stop;
- and
- a control device that rotationally drives said surveying optical system to set said surveying optical system at a predetermined position by first providing said first drive signal to said drive motor to drive said drive motor and then providing said second drive signal to said drive motor to drive said drive motor.
A surveying instrument comprising:
- a surveying optical system to be oriented toward a surveying target;
- a drive motor that drives said surveying optical system;
- a first drive control circuit that implements drive control on said drive motor at a first drive speed by outputting a first drive signal having a first frequency and a first pulse width;
- a second drive control circuit that implements drive control on said drive motor at a second drive speed lower than the first drive speed by outputting a second drive signal having a second frequency lower than the first frequency and a second pulse width larger than the first pulse width;
- and
- a control device that provides one of said first drive signal and said second drive signal to said drive motor.
A method for drive control of a surveying instrument, comprising:
- outputting a first drive signal so as to continuously drive a drive motor that rotationally drives a surveying optical system and outputting a second drive signal so as to drive the drive motor by allowing the drive motor to alternate accelerations and a virtual stop;
- and
- controlling a rotational drive of the surveying optical system so as to set the surveying optical system at a predetermined position by first providing the first drive signal to the drive motor and then providing the second drive signal to the drive motor.
A surveying instrument comprising:
- a surveying optical system to be oriented toward a surveying target;
- a drive motor that drives said surveying optical system;
- an encoder circuit that outputs a signal corresponding to an extent to which said surveying optical system is driven;
- a goniometric calculation circuit that performs goniometric calculation by using the signal output by said encoder circuit to determine a rotational angle of said surveying optical system;
- an interpolation calculation circuit that performs interpolation calculation of the rotational angle by using the signal output by said encoder circuit to determine a rotational optical angle;
- a first drive control circuit that outputs a first drive signal having a first frequency and a first pulse duty cycle and used to continuously drive said drive motor;
- a second drive control circuit that outputs a second drive signal having a second frequency lower than the first frequency of said first drive signal and a second pulse duty cycle with a second pulse width based upon the second frequency and the second pulse duty cycle, larger than the first pulse width based upon the first frequency and the first pulse duty cycle, so as to drive said drive motor by allowing said drive motor to alternate accelerations and a virtual stop;
- and
- a control device that rotationally drives said surveying optical system to set said surveying optical system at a predetermined position by first providing said first drive signal to said drive motor to drive said drive motor and then providing said second drive signal to said drive motor to drive said drive motor, wherein;
- said second drive control circuit changes at least one of the second pulse duty cycle and the second frequency of said second drive signal based upon the rotational angle and rotational interpolation angle determined by said goniometric calculation circuit and said interpolation calculation circuit.
Dependencies are inferred from the claim text.