Inertial sensor

1. An inertial sensor comprising:

an acceleration detecting element that detects a longitudinal acceleration of a vehicle and a lateral acceleration of the vehicle;

a first filter that limits a detection signal of the longitudinal acceleration and a detection signal of the lateral acceleration to a first band;

a second filter that limits the detection signal of the lateral acceleration to a second band that has a higher cut-off frequency than the first band;

a vehicle control variable calculation section that calculates a vehicle control variable of the vehicle on the basis of the detection signal of the lateral acceleration limited to the second band by the second filter and a lateral jerk that is a differential value of the lateral acceleration; and

a sensor signal output section that outputs the detection signal of the longitudinal acceleration and the detection signal of the lateral acceleration to an electronic control unit, both outputted detection signals being limited to the first band by the first filter, and outputs the vehicle control variable calculated by the vehicle control variable calculation section to the electronic control unit.

2. The inertial sensor according to claim 1 ,

wherein the vehicle control variable calculation section dynamically changes a gain or a bias of the vehicle control variable on the basis of a difference between values of the longitudinal acceleration of the vehicle.

3. The inertial sensor according to claim 1 ,

wherein the vehicle control variable calculation section dynamically changes a gain or a bias of the vehicle control variable according to a signal component that is applied to the acceleration detecting element.

4. The inertial sensor according to claim 1 , further comprising:

an angular velocity detecting element that detects at least one angular velocity;

a third filter that limits a detection signal of the angular velocity to a third band; and

a fourth filter that limits a detection signal of the angular velocity to a fourth band,

wherein the vehicle control variable calculation section calculates the vehicle control variable on the basis of the detection signal of the lateral acceleration limited to the second band and the detection signal of the angular velocity limited to the fourth band, and

wherein the sensor signal output section outputs the detection signal of the angular velocity limited to the third band and the vehicle control variable.

5. The inertial sensor according to claim 4 ,

wherein the fourth band has a higher cut-off frequency than the third band.

6. The inertial sensor according to claim 4 ,

wherein the angular velocity detecting element detects an angular velocity in a roll direction of the vehicle, and

wherein the vehicle control variable calculation section calculates the vehicle control variable using the lateral acceleration of the vehicle and the angular velocity in the roll direction of the vehicle.

7. The inertial sensor according to claim 6 ,

wherein the vehicle control variable calculation section dynamically changes a gain or a bias of the vehicle control variable on the basis of the longitudinal acceleration of the vehicle detected by the acceleration detecting element and the longitudinal acceleration of the vehicle calculated as the vehicle control variable.

8. The inertial sensor according to claim 6 ,

wherein the vehicle control variable calculation section dynamically changes a gain or a bias of the vehicle control variable according to a signal component that is applied to the angular velocity detecting element.

9. The inertial sensor according to claim 4 ,

wherein the sensor signal output section outputs the detection signal of the longitudinal acceleration limited to the first band, the detection signal of the lateral acceleration limited to the first band, the detection signal of the angular velocity limited to the third band and the vehicle control variable calculated by the vehicle control variable calculation section using the same communication frame.

10. A sensor system comprising:

a display section that displays a diagram in which a front-back direction acceleration and a lateral acceleration of a vehicle are respectively represented as two axes on a plane,

wherein a longitudinal acceleration and a lateral acceleration are output from an inertial sensor, wherein the inertial sensor comprises:

an acceleration detecting element that detects a longitudinal acceleration of a vehicle and a lateral acceleration of the vehicle;

a first filter that limits a detection signal of the longitudinal acceleration and a detection signal of the lateral acceleration to a first band;

a second filter that limits the detection signal of the lateral acceleration to a second band that has a higher cut-off frequency than the first band;

a vehicle control variable calculation section that calculates a vehicle control variable of the vehicle on the basis of the detection signal of the lateral acceleration limited to the second band by the second filter and a lateral jerk that is a differential value of the lateral acceleration; and

a sensor signal output section that outputs the detection signal of the longitudinal acceleration and the detection signal of the lateral acceleration to an electronic control unit, both outputted detection signals being limited to the first band by the first filter, and outputs the vehicle control variable calculated by the vehicle control variable calculation section to the electronic control unit,

wherein the longitudinal acceleration and the lateral acceleration output from the inertial sensor are displayed on the display section.