WO2022011435A1

WO2022011435A1 - Motorised apparatus and method for sports training

Info

Publication number: WO2022011435A1
Application number: PCT/AU2021/050771
Authority: WO
Inventors: Mark Fisher
Original assignee: Mark Fisher
Priority date: 2020-07-16
Filing date: 2021-07-16
Publication date: 2022-01-20

Abstract

A motorised apparatus for sports training having a closed loop control system based on sensors which are installed on the apparatus. An onboard computer controls the drive and steering to provide resistance or follow a path as determined by a training profile. The sensors include load cells at contact points for the athlete, and speed, location and direction sensors.

Description

MOTORISED APPARATUS AND METHOD FOR SPORTS TRAINING

FIELD OF THE INVENTION

This invention relates to apparatus for training athletes in sports requiring physical speed or strength, such as athletics, football or rugby. In particular, the invention relates to a motorised platform, cart or similar apparatus which can provide various modes of resistance to pushing or pulling by an athlete over ground. The invention also relates to a method of controlling the operation of the motorised apparatus.

BACKGROUND TO THE INVENTION

Injuries in athletes, particularly in their lower limbs can often be caused by unbalanced unilateral (single leg) horizontal forces. Types of injuries that can result include the following: hamstring, hip flexor, groin and knee ligament damage. An imbalance in these forces is an indicator for coaches and practitioners interested in performance monitoring and performance improvement in athletes and general public alike.

Training tools such as treadmills with integrated force measuring devices, stationary isokinetic dynamometers, static force plates both dual and single, and inner-soles equipped with force sensors and accelerometers have been available for many years. However, cost, limited portability and difficulty of extracting meaningful data has been an impediment to properly analysing athletic performance and training results.

A simple training system for lower limb strength has been a mobile sled that is pushed or towed across ground by an athlete. The sled can be weighted to increase friction with the ground and therefore the effort required by the athlete. A force measuring device may be provided either on the sled or in a tether through which the athlete is connected to the sled. However, the friction usually varies depending on the ground surface and only limited performance data is returned for evaluation. Simple carts with wheels lack useful control systems.

Some recent stationary devices utilise a motor driven drum of cord, that when attached to the athlete with a tether, can offer variable load and velocity limits, as the athlete sprints away. Monitoring the forces imparted by the athlete through torque requirements, and also the speed of the drum, can deliver useful data set such as stride length, stride rate, horizontal ground force. SUMMARY OF THE INVENTION

It is an object of the invention to provide a motorised alternative to existing training systems such as the sled, the cart or the drum, having a control system with a range of possible training profiles or modes for an athlete.

In one aspect the invention resides in motorised apparatus for sports training, including: a chassis having wheels or tracks which enable controlled movement of the apparatus over ground and which provide friction against sliding movement of the apparatus on the ground, a push and/or pull measuring system through which an athlete can apply a push or pull force to the apparatus during a training session, a processor and memory system which stores one or more control profiles for the apparatus, as required for training of the athlete, one or more drive motors in the chassis which provide torque to respective wheels or tracks, one or more motor controllers which receive commands from the processor to activate the respective motors and thereby drive and/or steer the apparatus, and one or more sensors which sense force applied by the athlete during the training session and provide feedback for the processor. Sensors which record speed and location are also generally provided.

In another aspect the invention resides in a method of controlling motorised apparatus for training an athlete, including: receiving a training profile, activating one or more drive and/or steer motors in the apparatus, sensing pushing or pulling force applied by the athlete to the apparatus, sensing location and speed of the apparatus, comparing sensor data with profile data, controlling the drive and/or steer motors in accord with the comparison, so that the apparatus leads or follows the athlete. Generally the sensor data is recorded in relation to performance of the athlete.

This invention preferably implements a controlled platform with sufficient friction through wheels or possibly tracks to inhibit sliding on the ground. Only when the onboard control system actively moves the platform can the athlete move the platform. Through closed loop motor control systems and sensory feedback such an apparatus can regulate modes of operation largely independent of the surface on which it operates.

Training modes can be of constant force or tension (Isotonic) regardless of the speed the athlete pushes or pulls the apparatus. Loads can be variable while velocity of the apparatus is held steady (Isokinetic) by an onboard controller. The apparatus can also provide a stationary resistance mode (Isometric). A profile could also be tailored on the supervisory device to suit a specific sport or position played by an athlete utilising a hybrid of simple modes. Embodiments of the apparatus can offer a testing range that makes full use of the grounds available. They may also track an athlete and remain directly behind, even when running a curved trajectory, utilising onboard camera technology, 3D force measurement, or line following technologies when used on a running track. The apparatus is preferably scalable, meaning smaller or larger systems can be built for sprint training or scrummaging, for example.

LIST OF FIGURES

Preferred embodiments of the invention will be described with respect to the drawings, of which:

Figures 1A, IB, 1C show motorised training apparatus in push, pull and overspeed modes of operation,

Figures 2A, 2B show components of a wheeled embodiment of the apparatus,

Figures 3A and 3B are schematic diagrams showing control of the motor or motors in the apparatus,

Figures 4, 5,6 outline athlete pushing, athlete pulling, athlete towed modes of operation, Figures 7, 8 provide detail for an enhanced athlete towed mode,

Figures 9A, 9B, 9C illustrate typical isokinetic, isotonic, isometric profiles,

Figures 10A, 10B schematically show the enhanced towing or overspeed mode,

Figure 11 shows a more complex sensor and control system for the motorised apparatus,

Figures 12A, 12B show preferred load cell sensors on the apparatus, and

Figures 13A, 13B, 13C show alternative drive and steering mechanisms for the apparatus.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings it will be appreciated that the invention can be provided as a range of different mobile platforms, carts or similar apparatus, for a range of different athletes and training purposes. These embodiments are described by way of example only. Figures 1A and IB show one-to-one training sessions of a coach and an athlete using pushing and pulling modes of a tracked platform 10. The platform may alternatively have 3, 4 or more wheels, so long as there is sufficient friction with the ground in either case. A range of different wheels or tracks may be used, such as omnidirectional wheels, to enable a range of possible forward or sideways steering actions. A microprocessor system on the platform controls resistance of the wheels as the athlete applies force.

An athlete 11 is either pushing the platform by way of a post or handle 12, or pulling the platform by way of a tether 13. A coach 14 is observing the athlete and wirelessly controlling the platform by way of a supervisory device 15 such as an IPAD. A particular platform may provide one or other or both pushing and pulling modes. Multiple athlete fittings may be provided for modes in involving team work or opposed athletes. The supervisory device typically transmits a required drive profile to a transceiver in the platform and receives measurements made by sensors in the platform, in order to evaluate performance of the athlete.

Figure 1C shows an additional overspeed or towing mode of operation in which the athlete 11 is sprinting and is pulled forwards by the platform, in a carefully controlled fashion using a tailored drive profile.

If the athlete 11 is to follow a non-linear path then the supervisory device 15 may also transmit path data having position coordinates and other path related data to the platform. Similarly if the athlete is permitted to steer the platform away from a linear path, in any mode, then then path limits and other data are required. An optional camera sensor 16 is also shown in these figures through which a processor in the platform is able to determine status of the athlete, such as which foot is currently in contact with the ground. This camera or other cameras may also provide additional functions such as environmental awareness.

Figures 2A and 2B show more detailed components of a preferred wheeled platform 20. Rear and front wheels 21 and 22 are mounted on a chassis or frame structure. Either set of wheels may be drive wheels and/or steering wheels. An athlete pulling or being towed by the platform is attached by a tether to towbar 23. An athlete or athletes pushing the platform engages with shoulder pads or handles 24. Load sensors 25 and 26 determine forces applied by the athlete through the towbar and pads respectively. These sensors may be 1, 2 or 3 axis load cells as required to provide suitable data for the coach. The load sensors could also be hydraulic rams which measure oil pressure, for example. Sensors 27, 28 are typically scanning depth cameras and/or lidar units for body tracking and collision avoidance. Additional load and therefore friction with the ground may be added to the platform by way of water tanks 29 if required. A radio transceiver on the platform provides wireless communication between an onboard motor and sensor control system, and one or more supervisory devices.

Tracking cameras 27, 28 mounted on the apparatus have several purposes. A body tracking camera can distinguish limbs and thereby be used to correlate data returned from the load cells 25, 26 with the left or right leg of the athlete. The results can then be used to determine whether one or other leg is weaker or stronger, or some other asymmetry, for example, or to reduce towing force when the athlete is mid air between contact with the ground. An environment tracking camera can be used to check whether the athlete or another person or object is in dangerous proximity to the platform, for collision avoidance. Other sensors such as laser ranging devices can be used to supplement the cameras.

The drive wheels 21 and/or 22 are powered by servo motors, with closed loop feedback. For a tracked vehicle there would generally one motor for each of the tracks on either side of the platform. In a cart with wheels, each wheel may have a separate motor and be independently steered or powered. Separate motors and controls allow the apparatus to be steered around a training area either directly in response to the athlete, or by a coach via the supervisory device. The platform could also have a secondary use in carrying other equipment onto a field for example.

Figure 3A schematically shows an onboard sensor and control system in more detail, in wireless communication with a supervisory device 30. These items are mounted in or on the chassis or frame. Left and right side motors 31, 32, are typically brushless AC or DC servo motors. A computer 33 including a processor and memory, sets targets for respective closed loop feedback systems which monitor motor speed and torque. Motor speed is typically determined via an encoder on the output shaft of the motor. Motor torque is determined via current requirements of the motor. Alternatively other sensors may be used for speed and torque. Error correction is also usually applied.

The computer 33 also receives signals from various sensors on the apparatus, such as the cameras mentioned above, laser ranging, the load cells, a line or gate detector, and a GPS position sensor.

The data in these signals is processed as required and transmitted through a transceiver Tx to the supervisory device 30. The computer also receives drive profiles for the motors which are converted into speed and torque targets for the feedback system. These profiles determine various training modes which are available in the apparatus. Path data may also be received for modes and profiles in which the platform may be steered by the athlete, by the coach or in accord with a particular profile. A simple non-linear path might involve circuits of a running track, for example, or following a course created by cones, flags, or electronic training gates.

The platform also typically provides visual and/or aural indicators for the athlete or others. These include ready to start, turning, proximity warnings, cart stopped, or indicate forces outside the particular profile.

Figure 3B outlines a feedback control loop operated by the computer 33. In step 34 the processor compares targets such as speed, load or direction from the current training profile stored in the memory, with data from one or sensors such as speed and location detectors, athlete force detectors, path sensors, cameras. Speed and torque or other corrections are calculated and supplied to motor command algorithms. The processor then provides output signals to motor controllers 35 which in turn activate the drive and/or steering motors as required. Then sensors observe operation 36 of the apparatus and provide feedback for comparison with the profile.

Figures 4, 5, 6 show overall operation of the motorised platform for each of the three modes pushing or pulling by the athlete, or overspeed towing by the platform. The coach selects a mode and uses the supervisory device 30 activate the onboard processor 33 which in turn activates the motors 31, 32. Alternatively the coach may manually activate the platform directly without using a wireless device, although wireless control is generally preferred. In each case the processor uses the profile to provide closed loop control 40, 50, 60 for the apparatus and provides audio/visual feedback 41, 51, 61 for the athlete.

Figures 7 outlines an enhanced towing or overspeed mode for sprinting athletes, in which the towing force is decreased or removed at times when the athlete is not in contact with the ground. The processor again uses a profile to provide closed loop control 70 for the apparatus and provides audio/visual feedback 71 for the athlete. A flight detection process 72 is used to estimate left and right foot contacts of the athlete with the ground. In this mode the flight detection process modifies a normal sprint profile as shown in Figure 8, by matching platform velocity to athlete deceleration 80 while in the air. The load or drag applied by the athlete is determined through a tether 13 and load cell such as shown in Figs IB or 1C.

Figures 9A, 9B, 9C respectively show simple isotonic, isokinetic and isometric drive profiles for the control system. In Figure 9A the motors provide a constant load or resistance while the athlete applies as much force as possible. The motor speed ramps up to a maximum then fades as the athlete tires. In Figure 9B, the athlete applies force in one way or another to the platform and the motor quickly ramps up to a steady target speed which is maintained regardless of the force. In Figure 9C, the apparatus remains stationary while the athlete applies a required force over a period of time, as shown by the dashed line.

Figures 10A and 10B provide further detail of the enhanced towing or overspeed mode. A single stride of a running athlete is shown in Fig 10A. Most of the distance covered during a stride occurs while the athlete is airborne in a flight phase. Force is applied through the ground over only a short portion of the stride and when the athlete speed is already declining. Fig 10B shows the speed variation as observed by sensors on the platform over multiple strides at the start of a five second sprint. An enhanced towed mode with flight detection would avoid applying force to the athlete during the flight phase of each stride. A feedback control system is generally useful to provide advanced features of this kind.

Figure 11 illustrates a more complex control process for the motorised training apparatus. In this example the apparatus has separate drive motors and steering motors. A computer receives target velocity, target force and steering mode information from a training profile. An array of one or more movement sensors 111, load sensors 112 and direction sensors 113 provide feedback for the computer. Velocity, force and steering error signals are calculated from the feedback data and the target information. The load sensors include x and y direction detectors in the athlete contact points. The direction sensors include z direction detectors in the contact points and a line tracking sensor. The movement sensors include a wheel speed encoder, GPS receiver and an accelerometer or magnetometer. A camera monitor may also be included. Various combinations of these and other sensors can be provided for particular coaching requirements. Based on the error signals the computer outputs motor drive and steering commands to respective controllers 114 and 115 for activation of the motors.

Figure 12A indicates how xyz load sensors may be placed at athlete contact points on the apparatus. These are typically the load cells 25 and 26 in Figures 2A, 2B. Figure 12B indicates how a torsional sensor can be included for a pushing configuration of the apparatus. Sensor data from these and the other sensors is recorded by the computer in relation to performance of the athlete. Recorded data is typically transmitted to the supervisory device when required.

Figures 13A, 13B, 13C illustrate a range of different drive and steering systems. The apparatus in Fig 13A includes a pair of drive motors for movement and athlete resistance, and an Ackermann steering system which has a separate servo (not shown). In Fig 13B four drive motors can be individually activated or braked to provide both resistance and steering. Fig 13C shows a three wheeled arrangement with a single drive wheel and motor, and an Ackermann steering system with a respective servo (not shown).

Claims

1. Motorised apparatus for sports training, including: a chassis having wheels or tracks which enable controlled movement of the apparatus over ground and which provide friction against sliding movement of the apparatus on the ground, a push and/or pull measuring system through which an athlete can apply a push or pull force to the apparatus during a training session, a processor and memory system which stores one or more control profiles for the apparatus, as required for training of the athlete, one or more drive motors in the chassis which provide torque to respective wheels or tracks, one or more motor controllers which receive commands from the processor to activate the respective motors and thereby drive and/or steer the apparatus, and one or more sensors which sense force applied by the athlete during the training session and provide feedback for the processor.

2. Apparatus according to claim 1 further including: one or more sensors which sense movement and/or location of the apparatus during the training session and provide feedback for the processor.

3. Apparatus according to claim 1 further including: a steering motor in the chassis which activates a steering system in the apparatus, and a controller for the steering motor which receives steering commands from the processor.

4 Apparatus according to claim 1 wherein driving of the motors includes providing braking or resistance to the athlete when pushing or pulling the apparatus.

5. Apparatus according to claim 1 wherein the sensors monitor x, y, z forces applied to the apparatus by the athlete and provide feedback signals to the processor so that the apparatus follows or leads the athlete as required by a control profile.

6. Apparatus according to claim 2 wherein the sensors monitor speed, location and direction of the apparatus and provide feedback signals to the processor so that the apparatus follows a path as required by a control profile.

7. Apparatus according to claim 1 further including an overspeed system through which the chassis can apply a towing force to the athlete during a training session.

8. Apparatus according to claim 1 wherein data communicated to and from the supervisory device includes control profile instructions for the processor, athlete force data measured by the push or pull system, and speed/position data for the apparatus.

9. Apparatus according to claim 1 wherein the control profiles include force and/or velocity targets for the motors.

10. Apparatus according to claim 1 wherein the control profiles include isokinetic, isotonic or isometric profiles for the motors.

11. Apparatus according to claim 1 wherein the push measuring system includes hand or shoulder contacts for the athlete and a 2D load cell, and the pull measuring system includes a tether, harness for the athlete and a 3D load cell.

12. Apparatus according to claim 1 wherein the motor drives include torque and speed feedback loops.

13. Apparatus according to claim 1 further including a safety system which provides collision avoidance and an auto stop.

14. Apparatus according to claim 1 having a weight adjustment system to assist friction with the ground.

15. Apparatus according to claim 1 further including: a wireless transceiver which communicates data between the processor and a supervisory device.

16. A method of controlling motorised apparatus for training an athlete, including: receiving a training profile, activating one or more drive and/or steer motors in the apparatus, sensing pushing or pulling force applied by the athlete to the apparatus, sensing location and speed of the apparatus, comparing sensor data with profile data, controlling the drive and/or steer motors in accord with the comparison, so that the apparatus leads or follows the athlete.

17. A method according to claim 16 further including recording sensor data in relation to performance of the athlete.