Granted Patent B2

US 12,722,218 · App. 17/619,680 · Granted Sep 1, 2026

Inventors: Martin Larsén (Jönköping, SE); Niklas Sarius (Jönköping, SE); Sören Kahl (Mjölby, SE); Per Norén (Nykil, SE)

Assignee: HUSQVARNA AB

B23D59/001B23D57/023B27B17/083

Abstract

Claims (72)

1 . A system for protecting an operator, the system comprising:

a power tool configured to be held by the operator;

a first set of wearable sensors configured to be worn by the operator;

a second set of wearable sensors configured to be worn by the operator;

a first tool sensor disposed at the power tool, the first tool sensor being configured to communicate with the first set of wearable sensors to determine motion tracking information;

a second tool sensor disposed at the power tool, the second tool sensor being configured to communicate with the second set of wearable sensors to determine distance information; and

a controller configured to determine, based on the motion tacking information and the distance information, whether to initiate a protective action with respect to the power tool,

wherein the motion tracking information provides high precision tracking of motion via directly inferred linear acceleration and angular velocity data in three dimensions at the operator,

wherein the controller is configured to prioritize the distance information over the motion tracking information within a predefined distance from the operator to the power tool represented by distance information between the second set of wearable sensors and the second tool sensor, and prioritize the motion tracking information over the distance information outside the predefined distance, and

wherein the predefined distance is only measured using the distance information measured using the second tool sensor and the second set of wearable sensors.

2 . The system of claim 1 , wherein the power tool is a chainsaw or other power equipment such as power cutters with blade or chain, and wherein the protective action comprises activating a chain brake of the chainsaw when one of the first set of wearable sensors or the second set of wearable sensors is within a threshold distance of a respective one of the first tool sensor or the second tool sensor, or when velocity of the power tool relative to the operator's body is above a threshold velocity, or when acceleration of the power tool relative to the operator's body is above a threshold acceleration.

3 . The system of claim 1 , wherein the power tool is a chainsaw or other power equipment such as power cutters with blade or chain, and wherein the protective action comprises providing an audible or visual warning to the operator when one of the first set of wearable sensors or the second set of wearable sensors is within a threshold distance of a respective one of the first tool sensor.

4 . The system of claim 1 , wherein the first set of wearable sensors comprises a plurality of inertial measurement unit (IMU)-based sensors, and the first tool sensor comprises tool position sensor, and

wherein the second set of wearable sensors comprises a plurality of distance sensors, and the second tool sensor comprises a reader disposed at the power tool.

5 . The system of claim 4 , wherein the IMU-based sensors and the tool position sensor are periodically calibrated based on predefined poses of the operator and corresponding positions of the power tool.

6 . The system of claim 5 , wherein the controller stores baseline data corresponding to known distances from each of the IMU-based sensors to the tool position sensor in each of the predefined poses,

wherein the controller is configured to perform a comparison of the baseline data to current data gathered in the predefined poses, and

wherein the controller is configured to reset errors associated with the IMU-based sensors based on the comparison.

7 . The system of claim 4 , wherein the controller is configured to obtain distance information from the plurality of distance sensors and the reader, and to obtain motion tracking information from the IMU-based sensors and the tool position sensor, and

wherein the controller is configured to prioritize the distance information over the motion tracking information within a predefined distance, and prioritize the motion tracking information over the distance information outside the predefined distance.

8 . The system of claim 4 , wherein the reader is a millimeter wave radar sensor with or without radar beam lenses.

9 . The system of claim 4 , wherein the reader is a radio, light or ultrasound transmitter, and

wherein the controller is configured to calculate distance information based on time of flight measurements associated with the reader and the plurality of distance sensors.

10 . The system of claim 4 , wherein the reader is an electromagnetic radio reader configured to detect electronic tags, and

wherein each of the plurality of distance sensors is an electronic tag.

11 . The system of claim 10 , wherein the controller is configured to:

a) increase transmit power until an instance of the electronic tag is detected;

b) reduce power until the instance of the electronic tag is no longer detected;

c) repeat steps a) and b) to determine a mean or average power at which the electronic tag is no longer detected; and

d) determine a range between the reader and the instance of the electronic tag based on the mean or average power.

12 . A system for protecting an operator, the system comprising:

a power tool configured to be held by the operator, wherein the power tool is a chainsaw or other power equipment such as power cutters with blade or chain;

a plurality of inertial measurement unit (IMU)-based sensors configured to be worn by the operator;

a plurality of distance sensors also worn by the operator;

a reader disposed at the power tool;

a tool position sensor disposed at the power tool; and

a controller configured to determine, based on measurements between the IMU-based sensors and the tool position sensor, whether to initiate a protective action with respect to the power tool,

wherein the IMU-based sensors and the tool position sensor are periodically calibrated based on predefined poses of the operator and corresponding positions of the power tool,

wherein the controller is configured to obtain distance information from the plurality of distance sensors and the reader, and to obtain motion tracking information from the IMU-based sensors and the tool position sensor,

wherein the motion tracking information provides high precision tracking of motion via directly inferred linear acceleration and angular velocity data in three dimensions,

wherein the controller is configured to prioritize the distance information over the motion tracking information within a predefined distance from the operator represented by the distance sensors to the power tool represented by the reader, and prioritize the motion tracking information over the distance information outside the predefined distance, and

wherein the predefined distance is only measured using the distance information measured between the plurality of distance sensors and the reader.

13 . The system of claim 12 , wherein the controller stores baseline data corresponding to known distances from each of the IMU-based sensors to the tool position sensor in each of the predefined poses,

wherein the controller is configured to perform a comparison of the baseline data to current data gathered in the predefined poses, and

wherein the controller is configured to reset errors associated with the IMU-based sensors based on the comparison.

14 . The system of claim 13 , further comprising a plurality of distance sensors also worn by the operator, and a reader disposed at the power tool.

15 . The system of claim 14 , wherein the controller is configured to obtain distance information from the plurality of distance sensors and the reader, and to obtain motion tracking information from the IMU-based sensors and the tool position sensor, and

wherein the controller is configured to prioritize the distance information over the motion tracking information within a predefined distance, and prioritize the motion tracking information over the distance information outside the predefined distance.

16 . The system of claim 12 , wherein the power tool is a chainsaw or other power equipment such as power cutters with blade or chain,

wherein the protective action comprises activating a chain brake of the chainsaw when one of the first set of wearable sensors or the second set of wearable sensors is within a threshold distance of a respective one of the first tool sensor of the second tool sensor, and/or

wherein the protective action comprises providing an audible or visual warning to the operator when one of the first set of wearable sensors or the second set of wearable sensors is within the threshold distance of a respective one of the first tool sensor of the second tool sensor, or when velocity of the power tool relative to the operator's body is above a threshold velocity, or when acceleration of the power tool relative to the operator's body is above a threshold acceleration.

17 . A system for protecting an operator, the system comprising:

a power tool configured to be held by the operator, wherein the power tool is a chainsaw or other power equipment such as power cutters with blade or chain;

a plurality of distance sensors configured to be worn by the operator;

a reader disposed at and powered by the power tool; and

a controller configured to determine, based on distances between each of the distance sensors and the reader, whether to initiate a protective action with respect to the power tool,

wherein the controller is configured to perform an adaptive power control cycle to determine the distances between each of the distance sensors and the reader,

wherein the adaptive power control cycle comprises varying transmission signal power via incrementally lowering the transmission signal power from an initial detection signal of the reader to determine an average power at which each of the distance sensors is no longer detected by the reader disposed at the power tool to determine an operation range between the operator represented by the distance sensors and the power tool represented by the reader,

wherein the initial detection signal is the transmission signal power at which the reader initially detects each of the distance sensors, and

wherein the controller is configured to determine the distances based on a comparison of the average power with previous power mapping information stored at the controller.

18 . The system of claim 17 , wherein the distance sensors are each electronic tags, and

wherein the adaptive power control cycle comprises:

a) increasing transmit power until an instance of the electronic tag is detected;

b) reduce power until the instance of the electronic tag is no longer detected;

c) repeat steps a) and b) to determine a mean or average power at which the electronic tag is no longer detected; and

d) determine a range between the reader and the instance of the electronic tag based on the mean or average power.

19 . The system of claim 18 , wherein the power tool is a chainsaw or other power equipment such as power cutters with blade or chain,

wherein the protective action comprises activating a chain brake of the chainsaw when one of the first set of wearable sensors or the second set of wearable sensors is within a threshold distance of a respective one of the first tool sensor or the second tool sensor or when velocity of the power tool relative to the operator's body is above a threshold velocity, or when acceleration of the power tool relative to the operator's body is above a threshold acceleration,

and/or

wherein the protective action comprises providing an audible or visual warning to the operator when one of the first set of wearable sensors or the second set of wearable sensors is within the threshold distance of a respective one of the first tool sensor or the second tool sensor.

20 . The system of claim 18 , further comprising a plurality of inertial measurement unit (IMU)-based sensors worn by the operator, and a tool position sensor disposed at the power tool,

wherein the controller is configured to determine, based on measurements between the IMU-based sensors and the tool position sensor, whether to initiate the protective action with respect to the power tool.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (88)