Weight sensing suspension truck for electric skateboard

Abstract

An electric skateboard with a hands free control mechanism includes weight sensors embedded in the front and rear truck base plates to measure both the total weight of the rider as well as their weight distribution on the deck. An advanced skate control circuit uses these weight signals from the base plate to control the motor power, and includes the ability to detect when the rider is kicking the board. During these kicking events, the skate control algorithm changes to a mode which minimises any rapid changes to the skateboard velocity so that the rider will remain stable with just one foot on the deck.

1 . An electric skateboard truck comprising:
 a base plate mountable to an underside of an electric skateboard deck and comprising a weight sensor positioned to directly or indirectly measure a force exerted on the base plate by the skateboard deck; and   a hanger pivotably coupled to the base plate, and comprising an axle for coupling to a pair of wheels.   
     
     
         2 . The electric skateboard truck as claimed in  claim 1 , wherein the base plate comprises a suspension spring, and the weight sensor is a strain gauge mounted on a flexing portion of the suspension spring that flexes when the truck is subjected to a rider weight. 
     
     
         3 . The electric skateboard truck as claimed in  claim 2  wherein the suspension spring is a leaf spring and the strain gauge is positioned on a flexible surface of the leaf spring. 
     
     
         4 . The electric skateboard truck as claimed in  claim 1  wherein the base plate comprises a suspension spring, and the weight sensor is a displacement sensor mounted on a displacing portion of the suspension spring that displaces when the truck is subjected to a rider weight. 
     
     
         5 . The electric skateboard truck as claimed in  claim 4  wherein the displacement sensor is selected from a group consisting: an optical sensor, a magnet and Hall effects detector, a capacitive sensor, and an inductive sensor. 
     
     
         6 . The electric skateboard truck as claimed in  claim 1  wherein the base plate comprises a planar section and a hanger mount section extending downwardly from the planar section and configured to couple to the hanger, and the weight sensor is a pressure sensitive resistor (FSR) sensor assembly mounted on top of the planar section and comprising a pair of plates sandwiching an FSR sensor. 
     
     
         7 . The electric skateboard truck as claimed in  claim 1  wherein the base plate comprises a planar section and a hanger mount section extending downwardly from the planar section and configured to couple to the hanger, the hanger mount section comprising a cut-out that causes a stress concentration in a location in the base plate when the truck is subjected to a rider weight, and wherein the weight sensor is a strain gauge located at the stress concentration location of the base plate. 
     
     
         8 . The electric skateboard truck as claimed in  claim 1  further comprising a pair of wheels coupled to the axle, and at least one motor rotationally coupled to the pair of wheels. 
     
     
         9 . The electric skateboard truck as claimed in  claim 8 , wherein the at least one motor comprises a motor mounted in a hub of each wheel of the pair of wheels. 
     
     
         10 . A truck kit for an electric skateboard, comprising:
 (a) a front truck comprising:
 a front base plate mountable to a front underside of an electric skateboard deck and comprising a front weight sensor positioned to directly or indirectly measure a force exerted on the front base plate by the skateboard deck; and 
 a front hanger pivotably coupled to the front base plate, and comprising a front axle for coupling to a front pair of wheels; and 
   (b) a rear truck comprising:
 a rear base plate mountable to a rear underside of the electric skateboard deck and comprising a rear weight sensor positioned to directly or indirectly measure a force exerted on the rear base plate by the skateboard deck; and 
 a rear hanger pivotably coupled to the rear base plate, and comprising a rear axle for coupling to a rear pair of wheels; 
   wherein at least one of the front and rear pair of wheels is rotatably drivable by at least one motor, and the at least one motor is controlled by at least one controller that is communicable with the front and rear weight sensors.   
     
     
         11 . The truck kit as claimed in  claim 10 , wherein the front and rear base plates comprise a front and rear suspension spring respectively, and the each of the front and rear weight sensors is a strain gauge mounted on a flexing portion of the front and rear suspension spring respectively. 
     
     
         12 . The truck kit as claimed in  claim 11  wherein each of the front and rear suspension springs is a leaf spring and the each of the front and rear strain gauges is positioned on a flexible surface of the front and rear leaf spring respectively. 
     
     
         13 . The truck kit as claimed in  claim 12  wherein the front and rear base plates comprise a front and rear suspension spring respectively, and each of the front and rear weight sensors is a displacement sensor mounted on a displacing portion of the front and rear suspension spring respectively. 
     
     
         14 . The truck kit as claimed in  claim 13  wherein the displacement sensor is selected from a group consisting: an optical sensor, a magnet and Hall effects detector, a capacitive sensor, and an inductive sensor. 
     
     
         15 . The truck kit as claimed in  claim 10  wherein the front and rear base plates each comprises a planar section and a hanger mount section extending downwardly from the planar section and configured to couple to the hanger, and the front and rear weight sensors each is a pressure sensitive resistor (FSR) sensor assembly mounted on top of the planar section and comprising a pair of plates sandwiching an FSR sensor. 
     
     
         16 . The truck kit as claimed in  claim 10  wherein the front and rear base plate each comprises a planar section and a hanger mount section extending downwardly from the planar section and configured to couple to the front and rear hanger respectively, each hanger mount section comprising a cut-out that causes a stress concentration in a location in the front and rear base plate respectively when the truck is subjected to a rider weight, and wherein each of the front and rear weight sensor is a strain gauge located at the stress concentration location of the front and rear base plate respectively. 
     
     
         17 . The truck kit as claimed in  claim 10  further comprising at least one controller electrically communicative with the front and rear weight sensors, and for electrically coupling to a motor. 
     
     
         18 . The truck kit at claimed in  claim 17  wherein the at least one controller comprises at least one skate controller circuit electrically communicative with the front and rear weight sensors, and at least one motor controller electrically communicative with the least one skate controller circuit and for electrically coupling to the motor. 
     
     
         19 . An electric skateboard, comprising:
 (a) a deck;   (b) at least one motor;   (c) a battery electrically coupled to the at least one motor;   (d) a front truck assembly comprising a front base plate mounted to a front underside of the deck and comprising a front weight sensor positioned to directly or indirectly measure a force exerted on the front base plate by the skateboard deck, and a front hanger pivotably coupled to the front base plate and comprising a front axle;   (e) a rear truck assembly comprising a rear base plate mounted to a rear underside of the deck and comprising a rear weight sensor positioned to directly or indirectly measure a force exerted on the rear base plate by the skateboard deck, and a rear hanger pivotably coupled to the rear base plate and comprising a rear axle;   (e) front and rear pairs of wheels, each pair of wheels mounted to the front and rear axles respectively, wherein at least one of the front and rear pairs of wheels is coupled to and rotatably driven by the at least one motor; and   (f) at least one controller communicative with the front and rear weight sensors and the at least one motor, and comprising a processor and a memory having encoded thereon program code executable by the processor to operate the at least one motor in response to measurements received from the front and rear weight sensors.   
     
     
         20 . A truck base plate for an electric skateboard, the truck base plate being mountable to an underside of an electric skateboard deck and pivotably mountable to a truck hanger, the truck base plate comprising a weight sensor positioned to directly or indirectly measure a force exerted on the truck base plate by the skateboard deck.