Wheel balancing apparatus and method with improved calibration and improved imbalance determination

A method of operating a wheel balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising;

• spinning said spindle about said axis for three calibration spins, each calibration spin comprising a plurality of revolutions of said spindle;
• sensing imbalance forces due to known calibration imbalances;
• determining a set of calibration coefficients for said wheel balancer from said sensed imbalance forces and from knowledge of said known calibration imbalances;
• and
• storing said set of calibration coefficients in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• wherein residual spindle imbalance data is obtained from sensor output signals from two of the three calibration spins.

A method of operating a wheel balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising;

• spinning said spindle about said axis for three calibration spins, each calibration spin comprising a plurality of revolutions of said spindle;
• sensing imbalance forces due to known calibration imbalances;
• determining a set of calibration coefficients for said wheel balancer from said sensed imbalance forces and from knowledge of said known calibration imbalances;
• and
• storing said set of calibration coefficients in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• wherein residual spindle imbalance data is obtained from sensor output signals from a single calibration spin.

A method of operating a wheel balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising;

• spinning said spindle about said axis a plurality of times;
• sensing imbalance forces due to known calibration imbalances;
• determining a set of calibration coefficients for said wheel balancer from said sensed imbalance forces and from knowledge of said known calibration imbalances;
• and
• storing said set of calibration coefficients in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• wherein the calibration coefficients are determined independently of any knowledge of the geometric relationships between the sensors and the rest of the balancer.

A method of operating a wheel balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising:

• spinning said spindle about said axis a plurality of calibration spins, each calibration spin comprising a plurality of revolutions of said spindle, at least two of the calibration spins being performed with known calibration imbalances secured to the spindle, the known calibration imbalances differing between said at least two calibration spins;
• sensing imbalance forces due to said known calibration imbalances;
• determining a set of calibration coefficients for said wheel balancer from said sensed imbalance forces and from knowledge of said known calibration imbalances;
• storing said set of calibration coefficients and additional calibration data in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• spinning a wheel/tire assembly mounted on the spindle;
• measuring and recording the corresponding output signals from said at least two sensors;
• and
• prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, iteratively determining the actual imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored additional calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly.

A method of operating a wheel balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising;

• spinning said spindle about said axis a plurality of times;
• sensing imbalance forces due to known calibration imbalances;
• determining a set of calibration coefficients for said wheel balancer from said sensed imbalance forces and from knowledge of said known calibration imbalances;
• storing said set of calibration coefficients and additional calibration data in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• and
• spinning a wheel/tire assembly mounted on the spindle, measuring and recording the corresponding output signals from said at least two sensors, and, prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, iteratively determining the actual imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored additional calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly;
• wherein the step of iteratively determining the actual imbalance of the wheel/tire assembly includes the step of initially selecting the sensor output signals obtained during the wheel/tire spin as trial values of sensor output signals.

A method of operating a wheel balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising;

• spinning said spindle about said axis a plurality of times;
• sensing imbalance forces due to known calibration imbalances;
• determining a set of calibration coefficients for said wheel balancer from said sensed imbalance forces and from knowledge of said known calibration imbalances;
• storing said set of calibration coefficients and additional calibration data in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• and
• spinning a wheel/tire assembly mounted on the spindle, measuring and recording the corresponding output signals from said at least two sensors, and iteratively determining the actual imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored additional calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly;
• wherein the step of iteratively determining the actual imbalance of the wheel/tire assembly includes the step of initially selecting the sensor output signals obtained during the wheel/tire spin as trial values of sensor output signals;
• wherein the step of iteratively determining the actual imbalance of the wheel/tire assembly includes the step of using said trial values and the calibration coefficients to estimate the imbalance of the wheel/tire assembly;
• and
• wherein the step of iteratively determining the actual imbalance of the wheel/tire assembly includes the step of calculating the sensor output signals which would result from the estimated imbalance by scaling the calibration data obtained during the calibration spins.

A wheel balancer comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning said spindle about an axis;
• at least two sensors for sensing imbalance forces;
• means for determining a set of calibration coefficients for said wheel balancer from sensed imbalance forces due to known calibration imbalances during a plurality of calibration spins and from said known calibration imbalances;
• and
• electronic memory means for storing said set of calibration coefficients for subsequent use in balancing a wheel/tire assembly;
• said electronic memory means having stored therein static calibration data which includes a known mass and known weight placement corresponding to at least one calibration spin and static calibration data which includes data representing each sensor output signal obtained during at least one calibration spin;
• said electronic memory means further having couple calibration data stored therein which includes a known force couple corresponding to at least one calibration spin.

A wheel balancer comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning said spindle about an axis;
• at least two sensors for sensing imbalance forces;
• means for determining a set of calibration coefficients for said wheel balancer from sensed imbalance forces due to known calibration imbalances during a plurality of calibration spins and from said known calibration imbalances, each calibration spin comprising a plurality of revolutions of said spindle, at least one of the calibration spins being performed with a first known calibration imbalance of the spindle and at least a second of the calibration spins being performed with a second known calibration imbalance of the spindle;
• and
• electronic memory means for storing said set of calibration coefficients for subsequent use in balancing a wheel/tire assembly;
• said determining means including means for iteratively determining the actual imbalance of a wheel/tire assembly mounted on the spindle, prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, by using the stored calibration coefficients, stored calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly.

A wheel balancer comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning said spindle about an axis;
• at least two sensors for sensing imbalance forces;
• means for determining a set of calibration coefficients for said wheel balancer from sensed imbalance forces due to known calibration imbalances during a plurality of calibration spins and from said known calibration imbalances, said determining means including means for extracting signal components of a predetermined frequency from the sensor output signals;
• and
• electronic memory means for storing said set of calibration coefficients for subsequent use in balancing a wheel/tire assembly;
• said extracting means including a digital signal processing chip and a Hamming window.

A wheel balancer comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning said spindle about an axis;
• at least two sensors for sensing imbalance forces;
• means for determining a set of calibration coefficients for said wheel balancer from sensed imbalance forces due to known calibration imbalances during a plurality of calibration spins and from said known calibration imbalances, said determining means includes means for extracting signal components of a predetermined frequency from the sensor output signals;
• and
• electronic memory means for storing said set of calibration coefficients for subsequent use in balancing a wheel/tire assembly;
• wherein the predetermined frequency corresponds to a nominal rotational speed of the spindle.

A method of operating a balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising:

• storing calibration coefficients in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• storing calibration data in electronic memory for subsequent use in balancing a wheel/tire assembly;
• spinning a wheel/tire assembly mounted on the spindle;
• measuring the corresponding output signals of the sensors;
• and
• prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, iteratively determining the imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly.

A method of operating a balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising:

• storing calibration coefficients in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• storing calibration data in electronic memory for subsequent use in balancing a wheel/tire assembly;
• spinning a wheel/tire assembly mounted on the spindle;
• measuring the corresponding output signals of the sensors;
• and
• prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, iteratively determining the imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly;
• said step of iteratively determining the imbalance of the wheel/tire assembly including the step of initially selecting the sensor output signals obtained during the wheel/tire spin as trial values of sensor output signals.

A method of operating a balancer, said balancer having a spindle for mounting a wheel/tire assembly thereon, means for spinning said spindle about an axis, and at least two sensors for sensing imbalance forces, said method comprising:

• storing calibration coefficients in an electronic memory for subsequent use in balancing a wheel/tire assembly;
• storing calibration data in electronic memory, for subsequent use in balancing a wheel/tire assembly;
• spinning a wheel/tire assembly mounted on the spindle;
• measuring the corresponding output signals of the sensors;
• and
• iteratively determining the imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored calibration data, and the measured sensor output signals corresponding to the spin of the mounted wheel/tire assembly;
• said step of iteratively determining the imbalance of the wheel/tire assembly including the step of initially selecting the sensor output signals obtained during the wheel/tire spin as trial values of sensor output signals;
• wherein the step of iteratively determining the imbalance of the wheel/tire assembly includes the step of using said trial values and the calibration coefficients to estimate the imbalance of the wheel/tire assembly;
• wherein the step of iteratively determining the imbalance of the wheel/tire assembly includes the step of calculating the sensor output signals which would result from the estimated imbalance by scaling and/or phase adjusting the calibration data.

Apparatus for measuring imbalance, said apparatus comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning the spindle about an axis;
• sensor means for measuring imbalance forces corresponding to the spin of the spindle mounted wheel/tire assembly;
• electronic memory means for storing calibration coefficients for subsequent use in balancing the wheel/tire assembly;
• electronic memory means for storing calibration data for subsequent use in balancing the wheel/tire assembly;
• and
• means for iteratively determining the imbalance of the wheel/tire assembly prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, using the stored calibration coefficients, the stored calibration data, and the measured imbalance forces corresponding to the spin of the mounted wheel/tire assembly.

Apparatus for measuring imbalance, said apparatus comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning the spindle about an axis;
• sensor means for measuring imbalance forces corresponding to the spin of the spindle mounted wheel/tire assembly;
• electronic memory means for storing calibration coefficients for subsequent use in balancing the wheel/tire assembly;
• electronic memory means for storing calibration data for subsequent use in balancing the wheel/tire assembly;
• and
• means for iteratively determining the imbalance of the wheel/tire assembly prior to adding any balance weights to the wheel/tire assembly to correct any imbalance thereof, using the stored calibration coefficients, the stored calibration data, and the measured imbalance forces corresponding to the spin of the mounted wheel/tire assembly;
• wherein said means for iteratively determining the imbalance of the wheel/tire assembly includes means for initially selecting the sensor output signals obtained during the wheel/tire spin as trial values of sensor output signals.

Apparatus for measuring imbalance, said apparatus comprising:

• a spindle for mounting a wheel/tire assembly thereon;
• means for spinning the spindle about an axis;
• sensor means for measuring imbalance forces corresponding to the spin of the spindle mounted wheel/tire assembly;
• electronic memory means for storing calibration coefficients for subsequent use in balancing the wheel/tire assembly;
• electronic memory means for storing calibration data for subsequent use in balancing the wheel/tire assembly;
• and
• means for iteratively determining the imbalance of the wheel/tire assembly using the stored calibration coefficients, the stored calibration data, and the measured imbalance forces corresponding to the spin of the mounted wheel/tire assembly;
• wherein said means for iteratively determining the imbalance of the wheel/tire assembly includes means for initially selecting the sensor output signals obtained during the wheel/tire spin as trial values of sensor output signals;
• wherein the means for iteratively determining the imbalance of the wheel/tire assembly includes means for using said trial values and the calibration coefficients to estimate the imbalance of the wheel/tire assembly;
• wherein the means for iteratively determining the imbalance of the wheel/tire assembly includes means for calculating the sensor output signals which would result from the estimated imbalance by scaling and/or phase adjusting the calibration data.