Method for monitoring lifting events at a construction site

1. A system comprising:

a body carried by a crane;

a lifting hook arranged below the body and configured to couple to a load;

a load sensor coupled to the body and configured to output load values representing forces carried from the lifting hook; and

a controller configured to:

access a first timeseries of load values output by the load sensor during loading of an object onto the lifting hook within a first time period;

derive a lifting profile of the object from the first timeseries of load values; and

identify a type of the object, carried by the lifting hook during the first time period, based on the lifting profile.

2. The system of claim 1 :

further comprising an optical sensor coupled to the body and facing downwardly toward the lifting hook; and

wherein the controller is configured to:

access a first image captured by the optical sensor during the first time period;

extract a first set of features from a foreground in the first image; and

identify the type of the object based on the lifting profile and the first set of features.

3. The system of claim 2 :

further comprising a wireless communication module; and

wherein the controller is configured to:

derive a weight of the object from the first timeseries of load values;

derive a dimension of the object from the first timeseries of load values and the first set of features;

generate a lift event record defining the type of the object, the weight of the object, and the dimension of the object; and

transmit the lift event record to a remote computer system via the wireless communication module.

4. The system of claim 1 :

further comprising an optical sensor coupled to the body and facing downwardly toward the lifting hook; and

wherein the controller is configured to:

access a first sequence of images captured by the optical sensor during the first time period;

extract a first sequence of features from foregrounds in the first sequence of images; and

track pitch and yaw orientations of the object during the first time period based on the first sequence of features.

5. The system of claim 4 :

further comprising a wireless communication module; and

wherein the controller is configured to:

derive a weight of the object from the first timeseries of load values;

generate a lift event record defining the type of the object, the weight of the object, and pitch and yaw orientations of the object during the first time period; and

transmit the lift event record to a remote computer system via the wireless communication module.

6. The system of claim 1 :

further comprising a geospatial position module coupled to the body and configured to output geospatial locations of the body; and

wherein the controller is configured to:

read a first geospatial location from the geospatial position module during loading of the object onto the crane hook within the first time period;

read a second geospatial location from the geospatial position module during unloading of the object from the crane hook within the first time period; and

generate a lift event record defining the type of the object, a pickup location of the object at the first geospatial location, and a drop-off location of the object at the second geospatial location.

7. The system of claim 6 :

further comprising an altimeter coupled to the body and configured to output altitude values representative of the altitude of the body; and

wherein the controller is configured to:

access a second timeseries of geospatial locations output by the geospatial position module during the first time period;

access a third timeseries of altitude values output by the altimeter during the first time period;

interpret a path of the object during the first time period based on the second timeseries of geospatial locations and the third timeseries of altitude values; and

generate the lift event record further comprising the path of the object.

8. The system of claim 1 :

further comprising a motion sensor coupled to the body and configured to output signals representing motion of the body; and

wherein the controller is configured to:

access a second timeseries of motion values output by the motion sensor following loading of the object onto the lifting hook within the first time period;

derive, from the first timeseries of load values, the lifting profile representing transition of weight of the object onto the lifting hook over a loading duration within the first time period;

derive, from the second timeseries of motion values, an oscillation characteristic representing swinging of the object over a transfer duration following the loading duration within the first time period; and

identify the type of the object based on the lifting profile and the oscillation characteristic.

9. The system of claim 1 , wherein the controller is configured to:

identify initial coupling of the object to the lifting hook at a first time in response to a first load value, represented in the first timeseries of load values, exceeding a threshold load value;

detect a peak load, in the first timeseries of load values, at a second time succeeding the first time;

derive, from the first timeseries of load values, the lifting profile representing loading of the crane hook, via the lifting hook, as a function of time from the first time to the second time;

characterize a slope of the lifting profile;

calculate an oscillation characteristic of the lifting profile; and

identify the type of the object based on the slope of the lifting profile and the oscillation characteristic of the lifting profile.

10. A system comprising:

a body carried by a crane;

a lifting hook arranged below the body and configured to couple to a load;

a motion sensor coupled to the body and configured to output motion values representing motion of the body; and

a controller configured to:

access a first timeseries of motion values output by the motion sensor following loading of an object onto the lifting hook within a first time period;

derive an oscillation characteristic of the object from the first timeseries of motion values; and

identify a type of the object based on the oscillation characteristic.

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

derive the oscillation characteristic of the object within a first frequency range from the first timeseries of motion values;

derive a second oscillation characteristic of the object, within a second frequency range greater than the first frequency range, from the first timeseries of motion values;

derive a dimension of the object based on the second oscillation characteristic; and

generate a lift event record defining the type of the object and the dimension of the object.

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

derive the oscillation characteristic comprising a pitch frequency of the object from the first timeseries of motion values;

derive a second oscillation characteristic comprising a natural frequency of the object from the first timeseries of motion values;

identify the object as elongated in response to the pitch frequency falling below a threshold frequency; and

in response to identifying the object as elongated:

identify the object as rebar in response to the natural frequency falling below a threshold frequency; and

identify the object as a steel beam in response to the natural frequency exceeding the threshold frequency.

13. The system of claim 10 :

further comprising a wireless communication module; and

wherein the controller is configured to:

derive the oscillation characteristic of the object within a first frequency range from the first timeseries of motion values;

derive a second oscillation characteristic of the object, within a second frequency range less than the first frequency range, from the first timeseries of motion values;

track pitch orientations of the object during the first time period based on the second oscillation characteristic;

generate a lift event record defining the type of the object and pitch orientations of the object during the first time period; and

transmit the lift event record to a remote computer system via the wireless communication module.

14. The system of claim 10 :

further comprising an optical sensor coupled to the body and facing downwardly toward the lifting hook; and

wherein the controller is configured to:

access a first image captured by the optical sensor during the first time period;

extract a first set of features from a foreground in the first image; and

identify the type of the object based on the oscillation characteristic and the first set of features.

15. The system of claim 14 :

further comprising:

a wireless communication module; and

a load sensor coupled to the body and configured to output load values representing forces carried from the lifting hook; and

wherein the controller is configured to:

derive a weight of the object from a load value output by the load sensor during the first time period;

derive a dimension of the object based on the oscillation characteristic and the first set of features;

generate a lift event record defining the type of the object, the weight of the object, and the dimension of the object; and

transmit the lift event record to a remote computer system via the wireless communication module.

16. The system of claim 10 :

further comprising a geospatial position module coupled to the body and configured to output geospatial locations of the body; and

wherein the controller is configured to:

read a first geospatial location from the geospatial position module during loading of the object onto the crane hook within the first time period;

read a second geospatial location from the geospatial position module during unloading of the object from the crane hook within the first time period; and

generate a lift event record defining the type of the object, a pickup location of the object at the first geospatial location, and a drop-off location of the object at the second geospatial location.

17. The system of claim 16 :

further comprising an altimeter coupled to the body and configured to output altitude values representative of the altitude of the body; and

wherein the controller is configured to:

access a second timeseries of geospatial locations output by the geospatial position module during the first time period;

access a third timeseries of altitude values output by the altimeter during the first time period;

interpret a path of the object during the first time period based on the second timeseries of geospatial locations and the third timeseries of altitude values; and

generate the lift event record further comprising the path of the object.

18. The system of claim 10 :

further comprising a load sensor coupled to the body and configured to output load values representing forces carried from the lifting hook; and

wherein the controller is configured to:

derive a weight of the object from a load value output by the load sensor during the first time period;

calculate a set of motion similarity scores for the object, each motion similarity score in the set of motion similarity scores representing similarity between the oscillation characteristic and a template oscillation characteristic of an object type in a set of object types;

calculate a set of load similarity scores for the object, each load similarity score in the set of load similarity scores representing proximity of the first weight of the object to a load range of an object type in the set of object types; and

identify the type of the object based on a combination of the set of motion similarity scores and the set of load similarity scores.

19. A system comprising:

a body carried by a crane;

a lifting hook arranged below the body and configured to couple to a load;

a motion sensor coupled to the body and configured to output motion values representing motion of the body;

an optical sensor coupled to the body and facing downwardly toward the lifting hook; and

a controller configured to:

access a first timeseries of motion values output by the motion sensor following loading of an object onto the lifting hook within a first time period;

derive an oscillation characteristic of the object from the first timeseries of motion values;

access a first image captured by the optical sensor during the first time period;

extract a first set of features from a foreground in the first image; and

identify a type of the object based on the oscillation characteristic and the first set of features.

20. The system of claim 1 :

further comprising a wireless communication module; and

wherein the controller is:

arranged within the body; and

configured to transmit the type of the object, carried by the lifting hook during the first time period, to a remote computer system via the wireless communication module.