Input device and load calculation method

A load calculation method performed in an input device including

• an operation surface configured to be pressed by a plurality of operating bodies,
• a position sensor configured to detect pressed positions on the operation surface, each of the pressed positions being a position pressed by one of the plurality of operating bodies,
• a plurality of load sensors each configured to detect, at a different location, a load applied to the operation surface from the plurality of operating bodies, the load sensors being configured to output values representing the detected loads as detection values, and
• a load calculation unit configured to calculate pressed point loads representing loads applied to the pressed positions respectively, based on the pressed positions and the detection values;
• the method comprising executing, by the load calculation unit, a calculation loop at least once in order to calculate the pressed point loads, the calculation loop including
• calculating, by using initial pressed point loads corresponding to the respective pressed positions, a plurality of computation values each representing a load to be detected at a corresponding load sensor of the load sensors, in a case of estimating that the initial pressed point loads are applied to the respective pressed positions in accordance with correspondence between the initial pressed point loads and the pressed positions;
• calculating, for each of the load sensors, a comparison value based on a comparison between the computation value and the detection value;
• calculating, for each of the pressed positions, an adjustment value used for adjusting the initial pressed point load, based on the comparison values and the pressed positions;
• and
• calculating, for each of the pressed positions, the pressed point load by adjusting the initial pressed point load based on the adjustment value;
• wherein, when the calculation loop is first executed, predetermined values are used as the initial pressed point loads.